diff --git a/Dockerfile b/Dockerfile
index bd87dd8..13a99b6 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -50,7 +50,6 @@ RUN apt-get update \
     && apt-get install -y yamllint \
     && apt-get autoremove -y \
     && apt-get clean \
-    && gem update --system \
     && bundle config set path.system true \
     && bundle config set jobs $(nproc) \
     && bundle install --gemfile=/Gemfile \
diff --git a/voxbox/Gemfile b/voxbox/Gemfile
index 08acd01..61aa7af 100644
--- a/voxbox/Gemfile
+++ b/voxbox/Gemfile
@@ -12,5 +12,6 @@ gem 'voxpupuli-acceptance', ENV['RUBYGEM_VOXPUPULI_ACCEPTANCE']
 gem 'voxpupuli-release',    ENV['RUBYGEM_VOXPUPULI_RELEASE']
 gem 'voxpupuli-test',       ENV['RUBYGEM_VOXPUPULI_TEST']
 gem 'rubocop-performance',  ENV['RUBYGEM_RUBOCOP_PERFORMANCE']
+gem 'ffi', '~> 1.16.3' # ffi 1.17.0 has change dependencies - see https://github.com/ffi/ffi/issues/1105
 
 # vim: syntax=ruby