diff --git a/.gitignore b/.gitignore
index 256cab0a7..93cd61d6d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,6 +5,7 @@ dist-newstyle
 cabal.sandbox.config
 .stack-work/
 .stack-work-bench/
+*.yaml.lock
 
 *.o
 *.hi
diff --git a/.travis.yml b/.travis.yml
index d1cceaf75..23b2e212c 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -24,40 +24,51 @@ before_cache:
 
 matrix:
   include:
+
     - env: BUILD=hlint CABALVER=2.2 GHCVER=8.4.4
       compiler: ": #GHC 8.4.4"
       addons: {apt: {packages: [cabal-install-2.2,ghc-8.4.4], sources: [hvr-ghc]}}
-    - env: BUILD=stack CABALVER=2.2 GHCVER=8.4.4 STACK_YAML=stack-bench.yaml
-      compiler: ": #GHC 8.4.4"
-      addons: {apt: {packages: [cabal-install-2.2,ghc-8.4.4], sources: [hvr-ghc]}}
-    - env: BUILD=stack CABALVER=2.2 GHCVER=8.4.4 STACK_YAML=stack-ffi-unescape.yaml
-      compiler: ": #GHC 8.4.4"
-      addons: {apt: {packages: [cabal-install-2.2,ghc-8.4.4], sources: [hvr-ghc]}}
+
+    - env: BUILD=stack CABALVER=2.4 GHCVER=8.6.5 STACK_YAML=stack-bench.yaml
+      compiler: ": #GHC 8.6.5"
+      addons: {apt: {packages: [cabal-install-2.4,ghc-8.6.5], sources: [hvr-ghc]}}
+
+    - env: BUILD=stack CABALVER=2.2 GHCVER=8.6.5 STACK_YAML=stack-ffi-unescape.yaml
+      compiler: ": #GHC 8.6.5"
+      addons: {apt: {packages: [cabal-install-2.2,ghc-8.6.5], sources: [hvr-ghc]}}
 
     - env: BUILD=cabal2 CABALVER=3.0 GHCVER=8.8.1
       compiler: ": #GHC 8.8.1"
       addons: {apt: {packages: [cabal-install-3.0,ghc-8.8.1], sources: [hvr-ghc]}}
+
     - env: BUILD=cabal CABALVER=2.4 GHCVER=8.6.5
       compiler: ": #GHC 8.6.5"
       addons: {apt: {packages: [cabal-install-2.4,ghc-8.6.5], sources: [hvr-ghc]}}
+
     - env: BUILD=cabal CABALVER=2.2 GHCVER=8.4.4
       compiler: ": #GHC 8.4.4"
       addons: {apt: {packages: [cabal-install-2.2,ghc-8.4.4], sources: [hvr-ghc]}}
+
     - env: BUILD=cabal CABALVER=2.0 GHCVER=8.2.2
       compiler: ": #GHC 8.2.2"
       addons: {apt: {packages: [cabal-install-2.0,ghc-8.2.2], sources: [hvr-ghc]}}
+
     - env: BUILD=cabal CABALVER=2.0 GHCVER=8.0.2
       compiler: ": #GHC 8.0.2"
       addons: {apt: {packages: [cabal-install-2.0,ghc-8.0.2], sources: [hvr-ghc]}}
+
     - env: BUILD=cabal CABALVER=1.22 GHCVER=7.10.3
       compiler: ": #GHC 7.10.3"
       addons: {apt: {packages: [cabal-install-1.22,ghc-7.10.3], sources: [hvr-ghc]}}
+
     - env: BUILD=cabal CABALVER=1.18 GHCVER=7.8.4
       compiler: ": #GHC 7.8.4"
       addons: {apt: {packages: [cabal-install-1.18,ghc-7.8.4], sources: [hvr-ghc]}}
+
     - env: BUILD=cabal CABALVER=1.18 GHCVER=7.6.3
       compiler: ": #GHC 7.6.3"
       addons: {apt: {packages: [cabal-install-1.18,ghc-7.6.3], sources: [hvr-ghc]}}
+
     - env: BUILD=cabal CABALVER=1.18 GHCVER=7.4.2
       compiler: ": #GHC 7.4.2"
       addons: {apt: {packages: [cabal-install-1.18,ghc-7.4.2], sources: [hvr-ghc]}}
diff --git a/stack-bench.yaml b/stack-bench.yaml
index 01ae37c22..4751576c3 100644
--- a/stack-bench.yaml
+++ b/stack-bench.yaml
@@ -1,4 +1,4 @@
-resolver: lts-12.26
+resolver: nightly-2019-09-21
 # We use aeson in the snapshot to
 # - avoid recompilation of criterion
 # - compare against it
@@ -9,10 +9,4 @@ resolver: lts-12.26
 work-dir: .stack-work-bench
 packages:
 - benchmarks
-extra-deps:
-- base-orphans-0.8.1
-- hashable-time-0.2.0.1
-- QuickCheck-2.13.1
-- quickcheck-instances-0.3.21
-- splitmix-0.0.2
-- time-compat-1.9.2.2
+extra-deps: []
diff --git a/stack-ffi-unescape.yaml b/stack-ffi-unescape.yaml
index 71b074ae6..a60276469 100644
--- a/stack-ffi-unescape.yaml
+++ b/stack-ffi-unescape.yaml
@@ -1,4 +1,4 @@
-resolver: lts-12.26
+resolver: nightly-2019-09-21
 packages:
 - '.'
 flags:
@@ -6,9 +6,4 @@ flags:
     fast: true
     cffi: true
 extra-deps:
-- base-orphans-0.8.1
-- hashable-time-0.2.0.1
-- QuickCheck-2.13.1
-- quickcheck-instances-0.3.21
-- splitmix-0.0.2
-- time-compat-1.9.2.2
+- Diff-0.4.0