diff --git a/build/docker/README.md b/build/docker/README.md
index a8d9501..4b59e03 100644
--- a/build/docker/README.md
+++ b/build/docker/README.md
@@ -134,25 +134,24 @@
 
 ## Compiler/Language Versions per Dockerfile ##
 
-Last updated: October 1, 2017
-
 | Language  | ubuntu-trusty | ubuntu-xenial | ubuntu-artful | Notes |
 | :-------- | :------------ | :------------ | :------------ | :---- |
+| as of     | Oct 01, 2017  | Jan 11, 2018  | Oct 01, 2017  |       |
 | as3       |               |               |               | Not in CI |
 | C++ gcc   | 4.8.4         | 5.4.0         | 7.2.0         |       |
 | C++ clang | 3.4           | 3.8           | 4.0           |       |
-| C# (mono) | 3.2.8.0       | 4.2.1         | 4.6.2.7       |       |
+| C# (mono) | 3.2.8.0       | 4.2.1.0       | 4.6.2.7       |       |
 | c_glib    | 2.40.2        | 2.48.2        | 2.54.0        |       |
 | cocoa     |               |               |               | Not in CI |
 | d         | 2.070.2       | 2.073.2       | 2.076.0       |       |
-| dart      | 1.20.1        | 1.24.2        | 1.24.2        |       |
+| dart      | 1.20.1        | 1.22.1        | 1.24.2        |       |
 | delphi    |               |               |               | Not in CI |
 | dotnet    |               | 2.0.3         | 2.0.3         |       |
 | erlang    | R16B03        | 18.3          | 20.0.4        |       |
 | go        | 1.2.1         | 1.6.2         | 1.8.3         |       |
 | haskell   | 7.6.3         | 7.10.3        | 8.0.2         |       |
 | haxe      |               | 3.2.1         | 3.4.2         | disabled in trusty builds - cores on install v3.0.0, disabled in artful builds - see THRIFT-4352 |
-| java      | 1.7.0_151     | 1.8.0_131     | 1.8.0_151     |       |
+| java      | 1.7.0_151     | 1.8.0_151     | 1.8.0_151     |       |
 | js        |               |               |               | Unsure how to look for version info? |
 | lua       | 5.1.5         | 5.2.4         | 5.2.4         | Lua 5.3: see THRIFT-4386 |
 | nodejs    |               | 4.2.6         | 8.9.1         | trusty has node.js 0.10.0 which is too old |
@@ -162,7 +161,8 @@
 | python    | 2.7.6         | 2.7.12        | 2.7.14        |       |
 | python3   | 3.4.3         | 3.5.2         | 3.6.3         |       |
 | ruby      | 1.9.3p484     | 2.3.1p112     | 2.3.3p222     |       |
-| rust      | 1.15.1        | 1.15.1        | 1.18.0        |       |
+| rust      | 1.15.1        | 1.17.0        | 1.18.0        |       |
 | smalltalk |               |               |               | Not in CI |
 | swift     |               |               |               | Not in CI |
 
+
diff --git a/build/docker/ubuntu-xenial/Dockerfile b/build/docker/ubuntu-xenial/Dockerfile
index a254a14..acf3d12 100644
--- a/build/docker/ubuntu-xenial/Dockerfile
+++ b/build/docker/ubuntu-xenial/Dockerfile
@@ -34,6 +34,7 @@
       apt-transport-https \
       apt-utils \
       curl \
+      software-properties-common \
       wget
 
 # csharp (mono)
@@ -41,7 +42,8 @@
 #     apt-key adv --keyserver keyserver.ubuntu.com --recv-keys A6A19B38D3D831EF
 
 # D
-RUN wget http://master.dl.sourceforge.net/project/d-apt/files/d-apt.list -O /etc/apt/sources.list.d/d-apt.list && \
+RUN apt-key adv --keyserver keyserver.ubuntu.com --recv-keys EBCF975E5BA24D5E && \
+    wget http://master.dl.sourceforge.net/project/d-apt/files/d-apt.list -O /etc/apt/sources.list.d/d-apt.list && \
     wget -qO - https://dlang.org/d-keyring.gpg | apt-key add -
 ENV D_VERSION 2.073.2-0
 
@@ -49,7 +51,7 @@
 RUN curl https://dl-ssl.google.com/linux/linux_signing_key.pub | apt-key add - && \
     curl https://storage.googleapis.com/download.dartlang.org/linux/debian/dart_stable.list > \
       /etc/apt/sources.list.d/dart_stable.list
-ENV DART_VERSION 1.24.2-1
+ENV DART_VERSION 1.22.1-1
 
 # dotnet (core)
 RUN curl https://packages.microsoft.com/keys/microsoft.asc | gpg --dearmor > /etc/apt/trusted.gpg.d/microsoft.gpg && \
@@ -152,8 +154,8 @@
       haxe \
       neko \
       neko-dev \
-      libneko0
-RUN haxelib setup --always /usr/share/haxe/lib && \
+      libneko0 && \
+    haxelib setup --always /usr/share/haxe/lib && \
     haxelib install --quiet --always hxcpp 3.4.64
 # note: hxcpp 3.4.185 (latest) no longer ships static libraries, and caused a build failure
 
diff --git a/lib/rb/thrift.gemspec b/lib/rb/thrift.gemspec
index 166a93f..c2533fd 100644
--- a/lib/rb/thrift.gemspec
+++ b/lib/rb/thrift.gemspec
@@ -29,7 +29,7 @@
 
   s.add_development_dependency 'rspec', ['>= 2.10.0', '< 2.14.0']
   s.add_development_dependency "rack", "~> 1.5"
-  s.add_development_dependency "rack-test", "~> 0.6"
+  s.add_development_dependency "rack-test", "< 0.8.0" # until we no longer build on trusty, then "~> 0.8.2"
   s.add_development_dependency "thin", "~> 1.5"
   s.add_development_dependency "bundler", "~> 1"
   s.add_development_dependency 'rake', '~> 10.5'