diff --git a/REQUIRE b/REQUIRE
index d5d6467..cbe39bf 100644
--- a/REQUIRE
+++ b/REQUIRE
@@ -1 +1,2 @@
 julia 0.4
+Compat 0.7.16
diff --git a/src/MetadataTools.jl b/src/MetadataTools.jl
index 41e9da5..0be20cc 100644
--- a/src/MetadataTools.jl
+++ b/src/MetadataTools.jl
@@ -12,6 +12,8 @@ module MetadataTools
 
 export get_pkg, get_all_pkg, get_upper_limit, get_pkg_info
 
+using Compat
+
 #-----------------------------------------------------------------------
 
 """
@@ -21,8 +23,8 @@ Represents a version of a package in METADATA.jl
 """
 immutable PkgMetaVersion
     ver::VersionNumber
-    sha::UTF8String
-    requires::Vector{UTF8String}
+    sha::Compat.UTF8String
+    requires::Vector{Compat.UTF8String}
 end
 function printer(io::IO, pmv::PkgMetaVersion)
     print(io, "  ", pmv.ver, ",", pmv.sha[1:6])
@@ -37,8 +39,8 @@ Base.show( io::IO, pmv::PkgMetaVersion) = printer(io,pmv)
 Represents a packages entry in METADATA.jl
 """
 immutable PkgMeta
-    name::UTF8String
-    url::UTF8String
+    name::Compat.UTF8String
+    url::Compat.UTF8String
     versions::Vector{PkgMetaVersion}
 end
 function printer(io::IO, pm::PkgMeta)
@@ -78,7 +80,7 @@ function get_pkg(pkg_name::AbstractString;
 
     url_path = joinpath(pkg_path,"url")
     !isfile(url_path) && error("Couldn't find url for $pkg_name (expected $url_path)")
-    url = chomp(readall(url_path))
+    url = chomp(readstring(url_path))
 
     vers_path = joinpath(pkg_path,"versions")
     !isdir(vers_path) &&
@@ -89,11 +91,11 @@ function get_pkg(pkg_name::AbstractString;
     for dir in readdir(vers_path)
         ver_num = convert(VersionNumber, dir)
         ver_path = joinpath(vers_path, dir)
-        sha = strip(readall(joinpath(ver_path,"sha1")))
+        sha = strip(readstring(joinpath(ver_path,"sha1")))
         req_path = joinpath(ver_path,"requires")
-        reqs = UTF8String[]
+        reqs = Compat.UTF8String[]
         if isfile(req_path)
-            req_file = map(strip,split(readall(req_path),"\n"))
+            req_file = map(strip,split(readstring(req_path),"\n"))
             for req in req_file
                 length(req) == 0 && continue
                 req[1] == '#' && continue
@@ -116,7 +118,7 @@ in the METADATA folder.
 function get_all_pkg(; meta_path=Pkg.dir("METADATA"))
     !isdir(meta_path) && error("Couldn't find METADATA folder at $meta_path")
 
-    pkgs = Dict{UTF8String,PkgMeta}()
+    pkgs = Dict{Compat.UTF8String,PkgMeta}()
     for fname in readdir(meta_path)
         # Skip files
         !isdir(joinpath(meta_path, fname)) && continue
diff --git a/src/pkg_graph.jl b/src/pkg_graph.jl
index a5fa61d..629bf59 100644
--- a/src/pkg_graph.jl
+++ b/src/pkg_graph.jl
@@ -20,8 +20,8 @@ package dependency graph.
 """
 type PkgGraph
     adjlist::Vector{Vector{Int}}
-    pkgnames::Vector{UTF8String}
-    pkgname_idx::Dict{UTF8String,Int}
+    pkgnames::Vector{Compat.UTF8String}
+    pkgname_idx::Dict{Compat.UTF8String,Int}
 end
 
 """
@@ -54,10 +54,10 @@ Given a Dict{UTF8String,PkgMeta} (e.g., from `get_all_pkg`), build a
 directed graph with an edge from PkgA to PkgB iff PkgA directly requires
 PkgB. Alternatively reverse the direction of the edges if `reverse` is true.
 """
-function make_dep_graph(pkgs::Dict{UTF8String,PkgMeta}; reverse=false)
+function make_dep_graph(pkgs::Dict{Compat.UTF8String,PkgMeta}; reverse=false)
     pkgnames = collect(keys(pkgs))
-    pkgname_idx = Dict{UTF8String,Int}(
-        [pkgname => i for (i,pkgname) in enumerate(pkgnames)])
+    pkgname_idx = Dict{Compat.UTF8String,Int}(
+        [(pkgname, i) for (i,pkgname) in enumerate(pkgnames)])  # TODO: Dict(pkgname=>i for ...)
     numpkg   = length(pkgnames)
     adjlist  = Vector{Int}[Vector{Int}() for pkgname in pkgnames]
 
@@ -139,8 +139,8 @@ function get_pkg_dep_graph(pkgname::AbstractString, pg::PkgGraph; depth=Inf)
         end
     end
     # Build subgraph
-    new_pkgnames = UTF8String["" for i in 1:new_n]
-    new_pkgname_idx = Dict{UTF8String,Int}()
+    new_pkgnames = Compat.UTF8String["" for i in 1:new_n]
+    new_pkgname_idx = Dict{Compat.UTF8String,Int}()
     new_adjlist  = Vector{Int}[Vector{Int}() for i in 1:new_n]
     for old_idx in 1:n
         !visited[old_idx] && continue