diff --git a/Cargo.lock b/Cargo.lock
index f4742622c379..08f4bac37476 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -271,7 +271,7 @@ dependencies = [
  "fnv 1.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "gleam 0.4.29 (registry+https://github.com/rust-lang/crates.io-index)",
  "ipc-channel 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "num-traits 0.1.37 (registry+https://github.com/rust-lang/crates.io-index)",
  "offscreen_gl_context 0.15.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_bytes 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -422,7 +422,7 @@ dependencies = [
  "image 0.18.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "ipc-channel 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.39 (registry+https://github.com/rust-lang/crates.io-index)",
- "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "msg 0.0.1",
  "net_traits 0.0.1",
  "nonzero 0.0.1",
@@ -458,7 +458,7 @@ dependencies = [
  "ipc-channel 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "itertools 0.7.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "layout_traits 0.0.1",
- "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "metrics 0.0.1",
  "msg 0.0.1",
  "net 0.0.1",
@@ -658,7 +658,7 @@ dependencies = [
 name = "debugger"
 version = "0.0.1"
 dependencies = [
- "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "ws 0.7.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -705,7 +705,7 @@ dependencies = [
  "hyper 0.10.13 (registry+https://github.com/rust-lang/crates.io-index)",
  "hyper_serde 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "ipc-channel 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "msg 0.0.1",
  "serde 1.0.27 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_json 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -840,11 +840,14 @@ dependencies = [
 
 [[package]]
 name = "env_logger"
-version = "0.4.3"
+version = "0.5.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "atty 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "humantime 1.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "regex 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "termcolor 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -984,9 +987,9 @@ dependencies = [
  "atomic_refcell 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "cssparser 0.23.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "cstr 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "env_logger 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "env_logger 0.5.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.39 (registry+https://github.com/rust-lang/crates.io-index)",
- "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "malloc_size_of 0.0.1",
  "nsstring 0.1.0",
  "parking_lot 0.5.4 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1022,7 +1025,7 @@ dependencies = [
  "ipc-channel 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.39 (registry+https://github.com/rust-lang/crates.io-index)",
- "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "malloc_size_of 0.0.1",
  "malloc_size_of_derive 0.0.1",
  "msg 0.0.1",
@@ -1191,6 +1194,14 @@ name = "httparse"
 version = "1.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "humantime"
+version = "1.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "quick-error 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "hyper"
 version = "0.10.13"
@@ -1409,7 +1420,7 @@ dependencies = [
  "html5ever 0.22.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "ipc-channel 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.39 (registry+https://github.com/rust-lang/crates.io-index)",
- "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "malloc_size_of 0.0.1",
  "msg 0.0.1",
  "net_traits 0.0.1",
@@ -1455,7 +1466,7 @@ dependencies = [
  "layout_traits 0.0.1",
  "lazy_static 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.39 (registry+https://github.com/rust-lang/crates.io-index)",
- "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "malloc_size_of 0.0.1",
  "metrics 0.0.1",
  "msg 0.0.1",
@@ -1554,14 +1565,14 @@ dependencies = [
  "debugger 0.0.1",
  "devtools 0.0.1",
  "devtools_traits 0.0.1",
- "env_logger 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "env_logger 0.5.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.17.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "gaol 0.0.1 (git+https://github.com/servo/gaol)",
  "gfx 0.0.1",
  "gleam 0.4.29 (registry+https://github.com/rust-lang/crates.io-index)",
  "ipc-channel 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "layout_thread 0.0.1",
- "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "msg 0.0.1",
  "net 0.0.1",
  "net_traits 0.0.1",
@@ -1713,7 +1724,7 @@ version = "0.0.1"
 dependencies = [
  "gfx_traits 0.0.1",
  "ipc-channel 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "malloc_size_of 0.0.1",
  "malloc_size_of_derive 0.0.1",
  "msg 0.0.1",
@@ -1876,7 +1887,7 @@ dependencies = [
  "immeta 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "ipc-channel 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "matches 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "mime 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "mime_guess 1.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1920,7 +1931,7 @@ dependencies = [
  "image 0.18.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "ipc-channel 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "malloc_size_of 0.0.1",
  "malloc_size_of_derive 0.0.1",
  "msg 0.0.1",
@@ -2246,7 +2257,7 @@ dependencies = [
  "ipc-channel 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "jemalloc-sys 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.39 (registry+https://github.com/rust-lang/crates.io-index)",
- "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "profile_traits 0.0.1",
  "regex 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.27 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2275,13 +2286,18 @@ dependencies = [
  "energy-monitor 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "energymon 0.3.0 (git+https://github.com/energymon/energymon-rust.git)",
  "ipc-channel 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.27 (registry+https://github.com/rust-lang/crates.io-index)",
  "servo_config 0.0.1",
  "signpost 0.1.0 (git+https://github.com/pcwalton/signpost.git)",
  "time 0.1.37 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "quick-error"
+version = "1.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "quote"
 version = "0.3.15"
@@ -2493,7 +2509,7 @@ dependencies = [
  "jstraceable_derive 0.0.1",
  "lazy_static 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.39 (registry+https://github.com/rust-lang/crates.io-index)",
- "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "malloc_size_of 0.0.1",
  "malloc_size_of_derive 0.0.1",
  "metrics 0.0.1",
@@ -2556,7 +2572,7 @@ dependencies = [
  "html5ever 0.22.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "ipc-channel 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.39 (registry+https://github.com/rust-lang/crates.io-index)",
- "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "malloc_size_of 0.0.1",
  "malloc_size_of_derive 0.0.1",
  "metrics 0.0.1",
@@ -2633,7 +2649,7 @@ dependencies = [
  "bitflags 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "cssparser 0.23.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "fnv 1.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "matches 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "phf 0.7.21 (registry+https://github.com/rust-lang/crates.io-index)",
  "phf_codegen 0.7.21 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2706,7 +2722,7 @@ dependencies = [
  "gleam 0.4.29 (registry+https://github.com/rust-lang/crates.io-index)",
  "glutin 0.13.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "libservo 0.0.1",
- "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "msg 0.0.1",
  "osmesa-src 17.3.1-devel (git+https://github.com/servo/osmesa-src)",
  "osmesa-sys 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2827,11 +2843,11 @@ name = "servo_config"
 version = "0.0.1"
 dependencies = [
  "android_injected_glue 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "env_logger 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "env_logger 0.5.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.17.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "getopts 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "num_cpus 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-serialize 0.3.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.27 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2858,7 +2874,7 @@ name = "servo_rand"
 version = "0.0.1"
 dependencies = [
  "lazy_static 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "uuid 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -2868,7 +2884,7 @@ name = "servo_remutex"
 version = "0.0.1"
 dependencies = [
  "lazy_static 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "nonzero 0.0.1",
 ]
 
@@ -3001,7 +3017,7 @@ dependencies = [
  "itoa 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "malloc_size_of 0.0.1",
  "malloc_size_of_derive 0.0.1",
  "matches 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3091,11 +3107,11 @@ dependencies = [
  "atomic_refcell 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "cssparser 0.23.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "cstr 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "env_logger 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "env_logger 0.5.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.17.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "geckoservo 0.0.1",
  "libc 0.2.39 (registry+https://github.com/rust-lang/crates.io-index)",
- "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "malloc_size_of 0.0.1",
  "regex 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "selectors 0.19.0",
@@ -3178,6 +3194,14 @@ dependencies = [
  "utf-8 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "termcolor"
+version = "0.3.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "wincolor 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "termion"
 version = "1.5.1"
@@ -3502,7 +3526,7 @@ dependencies = [
  "hyper 0.10.13 (registry+https://github.com/rust-lang/crates.io-index)",
  "image 0.18.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "ipc-channel 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "msg 0.0.1",
  "net_traits 0.0.1",
  "regex 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3575,7 +3599,7 @@ dependencies = [
  "canvas_traits 0.0.1",
  "euclid 0.17.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "ipc-channel 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "msg 0.0.1",
  "rust-webvr 0.9.10 (registry+https://github.com/rust-lang/crates.io-index)",
  "script_traits 0.0.1",
@@ -3630,6 +3654,14 @@ name = "winapi-x86_64-pc-windows-gnu"
 version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "wincolor"
+version = "0.1.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "winapi 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "winit"
 version = "0.11.2"
@@ -3827,7 +3859,7 @@ dependencies = [
 "checksum energymon-default-sys 0.3.0 (git+https://github.com/energymon/energymon-sys.git)" = "<none>"
 "checksum energymon-sys 0.3.0 (git+https://github.com/energymon/energymon-sys.git)" = "<none>"
 "checksum enum_primitive 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "be4551092f4d519593039259a9ed8daedf0da12e5109c5280338073eaeb81180"
-"checksum env_logger 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)" = "3ddf21e73e016298f5cb37d6ef8e8da8e39f91f9ec8b0df44b7deb16a9f8cd5b"
+"checksum env_logger 0.5.6 (registry+https://github.com/rust-lang/crates.io-index)" = "0561146661ae44c579e993456bc76d11ce1e0c7d745e57b2fa7146b6e49fa2ad"
 "checksum error-chain 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ff511d5dc435d703f4971bc399647c9bc38e20cb41452e3b9feb4765419ed3f3"
 "checksum euclid 0.17.2 (registry+https://github.com/rust-lang/crates.io-index)" = "adfe67a9343519c1449d208da5998c6de582de698f7a39c4ac82ffba23d131a5"
 "checksum expat-sys 2.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "c470ccb972f2088549b023db8029ed9da9426f5affbf9b62efff7009ab8ed5b1"
@@ -3858,6 +3890,7 @@ dependencies = [
 "checksum histogram 0.6.8 (registry+https://github.com/rust-lang/crates.io-index)" = "1bdcec4094c1ca961b685384ea7af76af5718230b3f34657d1a71fd2dcf4cc9d"
 "checksum html5ever 0.22.0 (registry+https://github.com/rust-lang/crates.io-index)" = "e579ac8647178ab915d400d7d22938bda5cd351c6c62e1c294d56884ccfc75fe"
 "checksum httparse 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "a6e7a63e511f9edffbab707141fbb8707d1a3098615fb2adbd5769cdfcc9b17d"
+"checksum humantime 1.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "0484fda3e7007f2a4a0d9c3a703ca38c71c54c55602ce4660c419fd32e188c9e"
 "checksum hyper 0.10.13 (registry+https://github.com/rust-lang/crates.io-index)" = "368cb56b2740ebf4230520e2b90ebb0461e69034d85d1945febd9b3971426db2"
 "checksum hyper-openssl 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)" = "85a372eb692590b3fe014c196c30f9f52d4c42f58cd49dd94caeee1593c9cc37"
 "checksum hyper_serde 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)" = "0997ad463f64ce6ba02cf5af320622bb9782e4f8355b650a2cc7ccca69a7cc2e"
@@ -3943,6 +3976,7 @@ dependencies = [
 "checksum precomputed-hash 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "925383efa346730478fb4838dbe9137d2a47675ad789c546d150a6e1dd4ab31c"
 "checksum proc-macro2 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "d1cb7aaaa4bf022ec2b14ff2f2ba1643a22f3cee88df014a85e14b392282c61d"
 "checksum procedural-masquerade 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "c93cdc1fb30af9ddf3debc4afbdb0f35126cbd99daa229dd76cdd5349b41d989"
+"checksum quick-error 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "eda5fe9b71976e62bc81b781206aaa076401769b2143379d3eb2118388babac4"
 "checksum quote 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)" = "7a6e920b65c65f10b2ae65c831a81a073a89edd28c7cce89475bff467ab4167a"
 "checksum quote 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)" = "1eca14c727ad12702eb4b6bfb5a232287dcf8385cb8ca83a3eeaf6519c44c408"
 "checksum rand 0.3.22 (registry+https://github.com/rust-lang/crates.io-index)" = "15a732abf9d20f0ad8eeb6f909bf6868722d9a06e1e50802b6a70351f40b4eb1"
@@ -3998,6 +4032,7 @@ dependencies = [
 "checksum synstructure 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "010366096045d8250555904c58da03377289e7f4b2ce7a5b1027e2b532f41000"
 "checksum tempfile 2.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "11ce2fe9db64b842314052e2421ac61a73ce41b898dc8e3750398b219c5fc1e0"
 "checksum tendril 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "9de21546595a0873061940d994bbbc5c35f024ae4fd61ec5c5b159115684f508"
+"checksum termcolor 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)" = "adc4587ead41bf016f11af03e55a624c06568b5a19db4e90fde573d805074f83"
 "checksum termion 1.5.1 (registry+https://github.com/rust-lang/crates.io-index)" = "689a3bdfaab439fd92bc87df5c4c78417d3cbe537487274e9b0b2dce76e92096"
 "checksum textwrap 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)" = "c0b59b6b4b44d867f1370ef1bd91bfb262bf07bf0ae65c202ea2fbc16153b693"
 "checksum thread-id 3.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "8df7875b676fddfadffd96deea3b1124e5ede707d4884248931077518cf1f773"
@@ -4046,6 +4081,7 @@ dependencies = [
 "checksum winapi-build 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "2d315eee3b34aca4797b2da6b13ed88266e6d612562a0c46390af8299fc699bc"
 "checksum winapi-i686-pc-windows-gnu 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)" = "ec6667f60c23eca65c561e63a13d81b44234c2e38a6b6c959025ee907ec614cc"
 "checksum winapi-x86_64-pc-windows-gnu 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)" = "98f12c52b2630cd05d2c3ffd8e008f7f48252c042b4871c72aed9dc733b96668"
+"checksum wincolor 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)" = "eeb06499a3a4d44302791052df005d5232b927ed1a9658146d842165c4de7767"
 "checksum winit 0.11.2 (registry+https://github.com/rust-lang/crates.io-index)" = "396f0350e661940359e3c8c7d58ff847f67997943e2c80ecac374c5aa8287f63"
 "checksum winres 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "27d9192d6356d7efe8405dec6c5506b67543cf64b6049968f39f4c4623b4f25d"
 "checksum ws 0.7.3 (registry+https://github.com/rust-lang/crates.io-index)" = "89c48c53bf9dee34411a08993c10b879c36e105d609b46e25673befe3a5c1320"
diff --git a/components/canvas/Cargo.toml b/components/canvas/Cargo.toml
index d99b799cea4b..b673e430da9b 100644
--- a/components/canvas/Cargo.toml
+++ b/components/canvas/Cargo.toml
@@ -18,7 +18,7 @@ euclid = "0.17"
 fnv = "1.0"
 gleam = "0.4.29"
 ipc-channel = "0.10"
-log = "0.3.5"
+log = "0.4"
 num-traits = "0.1.32"
 offscreen_gl_context = { version = "0.15", features = ["serde", "osmesa"] }
 serde_bytes = "0.10"
diff --git a/components/compositing/Cargo.toml b/components/compositing/Cargo.toml
index 083e41d5ab36..0948d0f0ae72 100644
--- a/components/compositing/Cargo.toml
+++ b/components/compositing/Cargo.toml
@@ -17,7 +17,7 @@ gleam = "0.4.29"
 image = "0.18"
 ipc-channel = "0.10"
 libc = "0.2"
-log = "0.3.5"
+log = "0.4"
 msg = {path = "../msg"}
 net_traits = {path = "../net_traits"}
 nonzero = {path = "../nonzero"}
diff --git a/components/config/Cargo.toml b/components/config/Cargo.toml
index 9daa698f6dc4..adcefa67156e 100644
--- a/components/config/Cargo.toml
+++ b/components/config/Cargo.toml
@@ -15,7 +15,7 @@ doctest = false
 euclid = "0.17"
 getopts = "0.2.11"
 lazy_static = "1"
-log = "0.3.5"
+log = "0.4"
 num_cpus = "1.1.0"
 rustc-serialize = "0.3"
 serde = "1.0"
@@ -24,7 +24,7 @@ servo_url = {path = "../url"}
 url = "1.2"
 
 [dev-dependencies]
-env_logger = "0.4"
+env_logger = "0.5"
 
 [target.'cfg(all(unix, not(target_os = "macos"), not(target_os = "ios"), not(target_os = "android")))'.dependencies]
 xdg = "2.0"
diff --git a/components/constellation/Cargo.toml b/components/constellation/Cargo.toml
index e7e82ea8e071..0d4c4d483ba0 100644
--- a/components/constellation/Cargo.toml
+++ b/components/constellation/Cargo.toml
@@ -25,7 +25,7 @@ hyper = "0.10"
 ipc-channel = "0.10"
 itertools = "0.7"
 layout_traits = {path = "../layout_traits"}
-log = "0.3.5"
+log = "0.4"
 metrics = {path = "../metrics"}
 msg = {path = "../msg"}
 net = {path = "../net"}
diff --git a/components/constellation/constellation.rs b/components/constellation/constellation.rs
index 738d992b8401..2da5835a2f9d 100644
--- a/components/constellation/constellation.rs
+++ b/components/constellation/constellation.rs
@@ -111,7 +111,7 @@ use ipc_channel::ipc::{self, IpcSender, IpcReceiver};
 use ipc_channel::router::ROUTER;
 use itertools::Itertools;
 use layout_traits::LayoutThreadFactory;
-use log::{Log, LogLevel, LogLevelFilter, LogMetadata, LogRecord};
+use log::{Log, Level, LevelFilter, Metadata, Record};
 use msg::constellation_msg::{BrowsingContextId, TopLevelBrowsingContextId, PipelineId};
 use msg::constellation_msg::{Key, KeyModifiers, KeyState};
 use msg::constellation_msg::{PipelineNamespace, PipelineNamespaceId, TraversalDirection};
@@ -438,17 +438,17 @@ impl FromScriptLogger {
     }
 
     /// The maximum log level the constellation logger is interested in.
-    pub fn filter(&self) -> LogLevelFilter {
-        LogLevelFilter::Warn
+    pub fn filter(&self) -> LevelFilter {
+        LevelFilter::Warn
     }
 }
 
 impl Log for FromScriptLogger {
-    fn enabled(&self, metadata: &LogMetadata) -> bool {
-        metadata.level() <= LogLevel::Warn
+    fn enabled(&self, metadata: &Metadata) -> bool {
+        metadata.level() <= Level::Warn
     }
 
-    fn log(&self, record: &LogRecord) {
+    fn log(&self, record: &Record) {
         if let Some(entry) = log_entry(record) {
             debug!("Sending log entry {:?}.", entry);
             let thread_name = thread::current().name().map(ToOwned::to_owned);
@@ -457,6 +457,8 @@ impl Log for FromScriptLogger {
             let _ = chan.send(msg);
         }
     }
+
+    fn flush(&self) {}
 }
 
 /// A logger directed at the constellation from the compositor
@@ -475,17 +477,17 @@ impl FromCompositorLogger {
     }
 
     /// The maximum log level the constellation logger is interested in.
-    pub fn filter(&self) -> LogLevelFilter {
-        LogLevelFilter::Warn
+    pub fn filter(&self) -> LevelFilter {
+        LevelFilter::Warn
     }
 }
 
 impl Log for FromCompositorLogger {
-    fn enabled(&self, metadata: &LogMetadata) -> bool {
-        metadata.level() <= LogLevel::Warn
+    fn enabled(&self, metadata: &Metadata) -> bool {
+        metadata.level() <= Level::Warn
     }
 
-    fn log(&self, record: &LogRecord) {
+    fn log(&self, record: &Record) {
         if let Some(entry) = log_entry(record) {
             debug!("Sending log entry {:?}.", entry);
             let top_level_id = TopLevelBrowsingContextId::installed();
@@ -495,22 +497,24 @@ impl Log for FromCompositorLogger {
             let _ = chan.send(msg);
         }
     }
+
+    fn flush(&self) {}
 }
 
-/// Rust uses `LogRecord` for storing logging, but servo converts that to
+/// Rust uses `Record` for storing logging, but servo converts that to
 /// a `LogEntry`. We do this so that we can record panics as well as log
-/// messages, and because `LogRecord` does not implement serde (de)serialization,
+/// messages, and because `Record` does not implement serde (de)serialization,
 /// so cannot be used over an IPC channel.
-fn log_entry(record: &LogRecord) -> Option<LogEntry> {
+fn log_entry(record: &Record) -> Option<LogEntry> {
     match record.level() {
-        LogLevel::Error if thread::panicking() => Some(LogEntry::Panic(
+        Level::Error if thread::panicking() => Some(LogEntry::Panic(
             format!("{}", record.args()),
             format!("{:?}", Backtrace::new())
         )),
-        LogLevel::Error => Some(LogEntry::Error(
+        Level::Error => Some(LogEntry::Error(
             format!("{}", record.args())
         )),
-        LogLevel::Warn => Some(LogEntry::Warn(
+        Level::Warn => Some(LogEntry::Warn(
             format!("{}", record.args())
         )),
         _ => None,
diff --git a/components/debugger/Cargo.toml b/components/debugger/Cargo.toml
index a5f2f4b4eabc..0f04322c80e7 100644
--- a/components/debugger/Cargo.toml
+++ b/components/debugger/Cargo.toml
@@ -11,5 +11,5 @@ path = "lib.rs"
 crate_type = ["rlib"]
 
 [dependencies]
-log = "0.3.5"
+log = "0.4"
 ws = "0.7.3"
diff --git a/components/devtools/Cargo.toml b/components/devtools/Cargo.toml
index c32d26e05ab0..fb80f609d848 100644
--- a/components/devtools/Cargo.toml
+++ b/components/devtools/Cargo.toml
@@ -14,7 +14,7 @@ devtools_traits = {path = "../devtools_traits"}
 hyper = "0.10"
 hyper_serde = "0.8"
 ipc-channel = "0.10"
-log = "0.3.5"
+log = "0.4"
 msg = {path = "../msg"}
 serde = "1.0"
 serde_json = "1.0"
diff --git a/components/gfx/Cargo.toml b/components/gfx/Cargo.toml
index d99fa2100d94..c231b6fe4eae 100644
--- a/components/gfx/Cargo.toml
+++ b/components/gfx/Cargo.toml
@@ -26,7 +26,7 @@ harfbuzz-sys = "0.1"
 ipc-channel = "0.10"
 lazy_static = "1"
 libc = "0.2"
-log = "0.3.5"
+log = "0.4"
 malloc_size_of = { path = "../malloc_size_of" }
 malloc_size_of_derive = { path = "../malloc_size_of_derive" }
 msg = {path = "../msg"}
diff --git a/components/layout/Cargo.toml b/components/layout/Cargo.toml
index e1d210be001f..798f91aa6cda 100644
--- a/components/layout/Cargo.toml
+++ b/components/layout/Cargo.toml
@@ -23,7 +23,7 @@ gfx_traits = {path = "../gfx_traits"}
 html5ever = "0.22"
 ipc-channel = "0.10"
 libc = "0.2"
-log = "0.3.5"
+log = "0.4"
 malloc_size_of = { path = "../malloc_size_of" }
 msg = {path = "../msg"}
 net_traits = {path = "../net_traits"}
diff --git a/components/layout_thread/Cargo.toml b/components/layout_thread/Cargo.toml
index e7c54e353df7..4bab2633a79f 100644
--- a/components/layout_thread/Cargo.toml
+++ b/components/layout_thread/Cargo.toml
@@ -26,7 +26,7 @@ layout = {path = "../layout"}
 layout_traits = {path = "../layout_traits"}
 lazy_static = "1"
 libc = "0.2"
-log = "0.3.5"
+log = "0.4"
 time = "0.1.17"
 malloc_size_of = { path = "../malloc_size_of" }
 metrics = {path = "../metrics"}
diff --git a/components/metrics/Cargo.toml b/components/metrics/Cargo.toml
index 5acdf4a0f323..105d95e2715c 100644
--- a/components/metrics/Cargo.toml
+++ b/components/metrics/Cargo.toml
@@ -12,7 +12,7 @@ path = "lib.rs"
 [dependencies]
 gfx_traits = {path = "../gfx_traits"}
 ipc-channel = "0.10"
-log = "0.3.5"
+log = "0.4"
 malloc_size_of = { path = "../malloc_size_of" }
 malloc_size_of_derive = { path = "../malloc_size_of_derive" }
 msg = {path = "../msg"}
diff --git a/components/net/Cargo.toml b/components/net/Cargo.toml
index b24ad31fa52c..b2dd5fd11346 100644
--- a/components/net/Cargo.toml
+++ b/components/net/Cargo.toml
@@ -23,7 +23,7 @@ hyper-openssl = "0.2.2"
 immeta = "0.3.6"
 ipc-channel = "0.10"
 lazy_static = "1"
-log = "0.3.5"
+log = "0.4"
 matches = "0.1"
 mime = "0.2.1"
 mime_guess = "1.8.0"
diff --git a/components/net/http_loader.rs b/components/net/http_loader.rs
index c1a8215b06ff..f1d18bda464d 100644
--- a/components/net/http_loader.rs
+++ b/components/net/http_loader.rs
@@ -410,7 +410,7 @@ fn obtain_response(connector: &Pool<Connector>,
             }
         }
 
-        if log_enabled!(log::LogLevel::Info) {
+        if log_enabled!(log::Level::Info) {
             info!("{} {}", method, url);
             for header in headers.iter() {
                 info!(" - {}", header);
@@ -1069,7 +1069,7 @@ fn http_network_fetch(request: &Request,
         Err(error) => return Response::network_error(error),
     };
 
-    if log_enabled!(log::LogLevel::Info) {
+    if log_enabled!(log::Level::Info) {
         info!("response for {}", url);
         for header in res.headers.iter() {
             info!(" - {}", header);
diff --git a/components/net_traits/Cargo.toml b/components/net_traits/Cargo.toml
index 1cdda589835a..b739e8ce9574 100644
--- a/components/net_traits/Cargo.toml
+++ b/components/net_traits/Cargo.toml
@@ -18,7 +18,7 @@ hyper_serde = "0.8"
 image = "0.18"
 ipc-channel = "0.10"
 lazy_static = "1"
-log = "0.3.5"
+log = "0.4"
 malloc_size_of = { path = "../malloc_size_of" }
 malloc_size_of_derive = { path = "../malloc_size_of_derive" }
 msg = {path = "../msg"}
diff --git a/components/profile/Cargo.toml b/components/profile/Cargo.toml
index 5ef8edbc8f7c..ff9b4788fb01 100644
--- a/components/profile/Cargo.toml
+++ b/components/profile/Cargo.toml
@@ -17,7 +17,7 @@ profile_traits = {path = "../profile_traits"}
 influent = "0.4"
 ipc-channel = "0.10"
 heartbeats-simple = "0.4"
-log = "0.3.5"
+log = "0.4"
 serde = "1.0"
 serde_json = "1.0"
 servo_config = {path = "../config"}
diff --git a/components/profile_traits/Cargo.toml b/components/profile_traits/Cargo.toml
index 3ea12bd6cfca..4bf33b5d79ff 100644
--- a/components/profile_traits/Cargo.toml
+++ b/components/profile_traits/Cargo.toml
@@ -17,7 +17,7 @@ bincode = "1"
 energy-monitor = {version = "0.2.0", optional = true}
 energymon = {git = "https://github.com/energymon/energymon-rust.git", optional = true}
 ipc-channel = "0.10"
-log = "0.3.5"
+log = "0.4"
 serde = "1.0"
 servo_config = {path = "../config"}
 signpost = {git = "https://github.com/pcwalton/signpost.git"}
diff --git a/components/rand/Cargo.toml b/components/rand/Cargo.toml
index 26657373172a..56e34c6ec27b 100644
--- a/components/rand/Cargo.toml
+++ b/components/rand/Cargo.toml
@@ -11,6 +11,6 @@ path = "lib.rs"
 
 [dependencies]
 lazy_static = "1"
-log = "0.3"
+log = "0.4"
 rand = "0.4"
 uuid = "0.6.2"
diff --git a/components/remutex/Cargo.toml b/components/remutex/Cargo.toml
index 844a5f1aede1..a91667e08cc7 100644
--- a/components/remutex/Cargo.toml
+++ b/components/remutex/Cargo.toml
@@ -13,5 +13,5 @@ doctest = false
 
 [dependencies]
 lazy_static = "1"
-log = "0.3.5"
+log = "0.4"
 nonzero = {path = "../nonzero"}
diff --git a/components/script/Cargo.toml b/components/script/Cargo.toml
index 2e6a60f6ddaf..93d64fddcfa8 100644
--- a/components/script/Cargo.toml
+++ b/components/script/Cargo.toml
@@ -55,7 +55,7 @@ ipc-channel = "0.10"
 jstraceable_derive = {path = "../jstraceable_derive"}
 lazy_static = "1"
 libc = "0.2"
-log = "0.3.5"
+log = "0.4"
 malloc_size_of = { path = "../malloc_size_of" }
 malloc_size_of_derive = { path = "../malloc_size_of_derive" }
 metrics = {path = "../metrics"}
diff --git a/components/script_layout_interface/Cargo.toml b/components/script_layout_interface/Cargo.toml
index f662ced9a356..4af1f6237c8b 100644
--- a/components/script_layout_interface/Cargo.toml
+++ b/components/script_layout_interface/Cargo.toml
@@ -19,7 +19,7 @@ gfx_traits = {path = "../gfx_traits"}
 html5ever = "0.22"
 ipc-channel = "0.10"
 libc = "0.2"
-log = "0.3.5"
+log = "0.4"
 time = "0.1.17"
 malloc_size_of = { path = "../malloc_size_of" }
 malloc_size_of_derive = { path = "../malloc_size_of_derive" }
diff --git a/components/script_layout_interface/reporter.rs b/components/script_layout_interface/reporter.rs
index 42adfa40d52a..c5f72460c4cd 100644
--- a/components/script_layout_interface/reporter.rs
+++ b/components/script_layout_interface/reporter.rs
@@ -26,7 +26,7 @@ impl ParseErrorReporter for CSSErrorReporter {
                     url: &ServoUrl,
                     location: SourceLocation,
                     error: ContextualParseError) {
-        if log_enabled!(log::LogLevel::Info) {
+        if log_enabled!(log::Level::Info) {
             info!("Url:\t{}\n{}:{} {}",
                   url.as_str(),
                   location.line,
diff --git a/components/selectors/Cargo.toml b/components/selectors/Cargo.toml
index 38b93e74a346..ee38f2ef2763 100644
--- a/components/selectors/Cargo.toml
+++ b/components/selectors/Cargo.toml
@@ -23,7 +23,7 @@ bench = []
 bitflags = "1.0"
 matches = "0.1"
 cssparser = "0.23.0"
-log = "0.3"
+log = "0.4"
 fnv = "1.0"
 phf = "0.7.18"
 precomputed-hash = "0.1"
diff --git a/components/servo/Cargo.toml b/components/servo/Cargo.toml
index ac3c9b84fae1..82f3188dade9 100644
--- a/components/servo/Cargo.toml
+++ b/components/servo/Cargo.toml
@@ -37,13 +37,13 @@ constellation = {path = "../constellation"}
 debugger = {path = "../debugger"}
 devtools = {path = "../devtools"}
 devtools_traits = {path = "../devtools_traits"}
-env_logger = "0.4"
+env_logger = "0.5"
 euclid = "0.17"
 gfx = {path = "../gfx"}
 gleam = "0.4.29"
 ipc-channel = "0.10"
 layout_thread = {path = "../layout_thread"}
-log = "0.3"
+log = "0.4"
 msg = {path = "../msg"}
 net = {path = "../net"}
 net_traits = {path = "../net_traits"}
diff --git a/components/servo/lib.rs b/components/servo/lib.rs
index e80e5ad7165c..fe394bce5b33 100644
--- a/components/servo/lib.rs
+++ b/components/servo/lib.rs
@@ -79,13 +79,13 @@ use constellation::{Constellation, InitialConstellationState, UnprivilegedPipeli
 use constellation::{FromCompositorLogger, FromScriptLogger};
 #[cfg(all(not(target_os = "windows"), not(target_os = "ios")))]
 use constellation::content_process_sandbox_profile;
-use env_logger::Logger as EnvLogger;
+use env_logger::Builder as EnvLoggerBuilder;
 use euclid::Length;
 #[cfg(all(not(target_os = "windows"), not(target_os = "ios")))]
 use gaol::sandbox::{ChildSandbox, ChildSandboxMethods};
 use gfx::font_cache_thread::FontCacheThread;
 use ipc_channel::ipc::{self, IpcSender};
-use log::{Log, LogMetadata, LogRecord};
+use log::{Log, Metadata, Record};
 use net::resource_thread::new_resource_threads;
 use net_traits::IpcSend;
 use profile::mem as profile_mem;
@@ -404,14 +404,13 @@ impl<Window> Servo<Window> where Window: WindowMethods + 'static {
 
     pub fn setup_logging(&self) {
         let constellation_chan = self.constellation_chan.clone();
-        log::set_logger(|max_log_level| {
-            let env_logger = EnvLogger::new();
-            let con_logger = FromCompositorLogger::new(constellation_chan);
-            let filter = max(env_logger.filter(), con_logger.filter());
-            let logger = BothLogger(env_logger, con_logger);
-            max_log_level.set(filter);
-            Box::new(logger)
-        }).expect("Failed to set logger.")
+        let env_logger = EnvLoggerBuilder::new().build();
+        let con_logger = FromCompositorLogger::new(constellation_chan);
+        let filter = max(env_logger.filter(), con_logger.filter());
+        log::set_max_level(filter);
+
+        let logger = BothLogger(env_logger, con_logger);
+        log::set_boxed_logger(Box::new(logger)).expect("Failed to set logger.");
     }
 
     pub fn deinit(self) {
@@ -548,25 +547,29 @@ fn create_constellation(user_agent: Cow<'static, str>,
 struct BothLogger<Log1, Log2>(Log1, Log2);
 
 impl<Log1, Log2> Log for BothLogger<Log1, Log2> where Log1: Log, Log2: Log {
-    fn enabled(&self, metadata: &LogMetadata) -> bool {
+    fn enabled(&self, metadata: &Metadata) -> bool {
         self.0.enabled(metadata) || self.1.enabled(metadata)
     }
 
-    fn log(&self, record: &LogRecord) {
+    fn log(&self, record: &Record) {
         self.0.log(record);
         self.1.log(record);
     }
+
+    fn flush(&self) {
+        self.0.flush();
+        self.1.flush();
+    }
 }
 
 pub fn set_logger(script_to_constellation_chan: ScriptToConstellationChan) {
-    log::set_logger(|max_log_level| {
-        let env_logger = EnvLogger::new();
-        let con_logger = FromScriptLogger::new(script_to_constellation_chan);
-        let filter = max(env_logger.filter(), con_logger.filter());
-        let logger = BothLogger(env_logger, con_logger);
-        max_log_level.set(filter);
-        Box::new(logger)
-    }).expect("Failed to set logger.")
+    let env_logger = EnvLoggerBuilder::new().build();
+    let con_logger = FromScriptLogger::new(script_to_constellation_chan);
+    let filter = max(env_logger.filter(), con_logger.filter());
+    log::set_max_level(filter);
+
+    let logger = BothLogger(env_logger, con_logger);
+    log::set_boxed_logger(Box::new(logger)).expect("Failed to set logger.");
 }
 
 /// Content process entry point.
diff --git a/components/style/Cargo.toml b/components/style/Cargo.toml
index d3a1d04f4d27..ee9f914ffa6c 100644
--- a/components/style/Cargo.toml
+++ b/components/style/Cargo.toml
@@ -42,7 +42,7 @@ html5ever = {version = "0.22", optional = true}
 itertools = "0.7.6"
 itoa = "0.3"
 lazy_static = "1"
-log = "0.3"
+log = "0.4"
 malloc_size_of = { path = "../malloc_size_of" }
 malloc_size_of_derive = { path = "../malloc_size_of_derive" }
 matches = "0.1"
@@ -77,7 +77,7 @@ kernel32-sys = "0.2"
 
 [build-dependencies]
 lazy_static = "1"
-log = "0.3"
+log = "0.4"
 bindgen = { version = "0.33.2", optional = true, default-features = false }
 regex = {version = "0.2", optional = true}
 walkdir = "1.0"
diff --git a/components/style/error_reporting.rs b/components/style/error_reporting.rs
index c1446eaa0a0a..d3cbea500ae7 100644
--- a/components/style/error_reporting.rs
+++ b/components/style/error_reporting.rs
@@ -207,7 +207,7 @@ impl ParseErrorReporter for RustLogReporter {
                     url: &UrlExtraData,
                     location: SourceLocation,
                     error: ContextualParseError) {
-        if log_enabled!(log::LogLevel::Info) {
+        if log_enabled!(log::Level::Info) {
             info!("Url:\t{}\n{}:{} {}", url.as_str(), location.line, location.column, error)
         }
     }
diff --git a/components/style/style_resolver.rs b/components/style/style_resolver.rs
index 99cc0ac33638..c0ac24063bc0 100644
--- a/components/style/style_resolver.rs
+++ b/components/style/style_resolver.rs
@@ -8,7 +8,7 @@ use applicable_declarations::ApplicableDeclarationList;
 use context::{CascadeInputs, ElementCascadeInputs, StyleContext};
 use data::{ElementStyles, EagerPseudoStyles};
 use dom::TElement;
-use log::LogLevel::Trace;
+use log::Level::Trace;
 use matching::MatchMethods;
 use properties::{AnimationRules, ComputedValues};
 use properties::longhands::display::computed_value::T as Display;
diff --git a/components/webdriver_server/Cargo.toml b/components/webdriver_server/Cargo.toml
index dbca178d48d5..421d3defe57a 100644
--- a/components/webdriver_server/Cargo.toml
+++ b/components/webdriver_server/Cargo.toml
@@ -16,7 +16,7 @@ euclid = "0.17"
 hyper = "0.10"
 image = "0.18"
 ipc-channel = "0.10"
-log = "0.3.5"
+log = "0.4"
 msg = {path = "../msg"}
 net_traits = {path = "../net_traits"}
 regex = "0.2"
diff --git a/components/webvr/Cargo.toml b/components/webvr/Cargo.toml
index c220d2dde5d9..337f5f4861a0 100644
--- a/components/webvr/Cargo.toml
+++ b/components/webvr/Cargo.toml
@@ -17,7 +17,7 @@ oculusvr = ['rust-webvr/oculusvr']
 canvas_traits = {path = "../canvas_traits"}
 euclid = "0.17"
 ipc-channel = "0.10"
-log = "0.3"
+log = "0.4"
 msg = {path = "../msg"}
 rust-webvr = {version = "0.9", features = ["openvr"]}
 script_traits = {path = "../script_traits"}
diff --git a/ports/geckolib/Cargo.toml b/ports/geckolib/Cargo.toml
index 0af92e74dc1c..a22080ce1c8c 100644
--- a/ports/geckolib/Cargo.toml
+++ b/ports/geckolib/Cargo.toml
@@ -17,9 +17,9 @@ gecko_debug = ["style/gecko_debug"]
 atomic_refcell = "0.1"
 cssparser = "0.23.0"
 cstr = "0.1.2"
-env_logger = {version = "0.4", default-features = false} # disable `regex` to reduce code size
+env_logger = {version = "0.5", default-features = false} # disable `regex` to reduce code size
 libc = "0.2"
-log = {version = "0.3.5", features = ["release_max_level_info"]}
+log = {version = "0.4", features = ["release_max_level_info"]}
 malloc_size_of = {path = "../../components/malloc_size_of"}
 nsstring = {path = "../../support/gecko/nsstring"}
 parking_lot = "0.5"
diff --git a/ports/geckolib/glue.rs b/ports/geckolib/glue.rs
index 3381da47e0b0..d12b2b603014 100644
--- a/ports/geckolib/glue.rs
+++ b/ports/geckolib/glue.rs
@@ -4,7 +4,7 @@
 
 use cssparser::{ParseErrorKind, Parser, ParserInput};
 use cssparser::ToCss as ParserToCss;
-use env_logger::LogBuilder;
+use env_logger::Builder;
 use malloc_size_of::MallocSizeOfOps;
 use selectors::NthIndexCache;
 use selectors::matching::{MatchingContext, MatchingMode, matches_selector};
@@ -180,11 +180,11 @@ pub extern "C" fn Servo_Initialize(dummy_url_data: *mut URLExtraData) {
     use style::gecko_bindings::sugar::origin_flags;
 
     // Initialize logging.
-    let mut builder = LogBuilder::new();
+    let mut builder = Builder::new();
     let default_level = if cfg!(debug_assertions) { "warn" } else { "error" };
     match env::var("RUST_LOG") {
-      Ok(v) => builder.parse(&v).init().unwrap(),
-      _ => builder.parse(default_level).init().unwrap(),
+      Ok(v) => builder.parse(&v).init(),
+      _ => builder.parse(default_level).init(),
     };
 
     // Pretend that we're a Servo Layout thread, to make some assertions happy.
diff --git a/ports/geckolib/tests/Cargo.toml b/ports/geckolib/tests/Cargo.toml
index 01ffb1121d50..0d670f2ec3d9 100644
--- a/ports/geckolib/tests/Cargo.toml
+++ b/ports/geckolib/tests/Cargo.toml
@@ -15,11 +15,11 @@ doctest = false
 atomic_refcell = "0.1"
 cssparser = "0.23.0"
 cstr = "0.1.2"
-env_logger = { version = "0.4", default-features = false }
+env_logger = { version = "0.5", default-features = false }
 euclid = "0.17"
 geckoservo = {path = "../../../ports/geckolib"}
 libc = "0.2"
-log = {version = "0.3.5", features = ["release_max_level_info"]}
+log = {version = "0.4", features = ["release_max_level_info"]}
 malloc_size_of = {path = "../../../components/malloc_size_of"}
 selectors = {path = "../../../components/selectors"}
 size_of_test = {path = "../../../components/size_of_test"}
diff --git a/ports/servo/Cargo.toml b/ports/servo/Cargo.toml
index b2e28109d346..0d2d01aebf08 100644
--- a/ports/servo/Cargo.toml
+++ b/ports/servo/Cargo.toml
@@ -41,7 +41,7 @@ euclid = "0.17"
 gleam = "0.4.29"
 glutin = "0.13"
 libservo = {path = "../../components/servo"}
-log = "0.3.5"
+log = "0.4"
 msg = {path = "../../components/msg"}
 script_traits = {path = "../../components/script_traits"}
 servo_geometry = {path = "../../components/geometry"}