diff --git a/.circleci/config.yml b/.circleci/config.yml
index 6e7dd560..90ae4c57 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -1,66 +1,54 @@
-version: 2
+version: 2.1
 
 workflows:
   version: 2
   test:
     jobs:
-      - test-2.5
-      - test-2.6
-      - test-2.7
-      - test-3.0
-      - test-jruby-9.2
-
-ruby-docker-template: &ruby-docker-template
-  steps:
-    - checkout
-    - run: |
-        if [[ $CIRCLE_JOB == test-jruby* ]]; then
-          gem install jruby-openssl; # required by bundler, no effect on Ruby MRI
-          sudo apt-get update -y && sudo apt-get install -y build-essential
-        fi
-    - run: ruby -v
-    - run: gem install bundler
-    - run: bundle install
-    - run: mkdir ./rspec
-    - run: bundle exec rspec --format progress --format RspecJunitFormatter -o ./rspec/rspec.xml spec
-    - store_test_results:
-        path: ./rspec
-    - store_artifacts:
-        path: ./rspec
+      - build-test-linux:
+          name: Ruby 2.5
+          docker-image: cimg/ruby:2.5
+      - build-test-linux:
+          name: Ruby 2.6
+          docker-image: cimg/ruby:2.6
+      - build-test-linux:
+          name: Ruby 2.7
+          docker-image: cimg/ruby:2.7
+      - build-test-linux:
+          name: Ruby 3.0
+          docker-image: cimg/ruby:3.0
+      - build-test-linux:
+          name: JRuby 9.2
+          docker-image: circleci/jruby:9.2-jdk
+          jruby: true
 
 jobs:
-  test-2.5:
-    <<: *ruby-docker-template
-    docker:
-      - image: circleci/ruby:2.5
-      - image: consul
-      - image: redis
-      - image: amazon/dynamodb-local
-  test-2.6:
-    <<: *ruby-docker-template
-    docker:
-      - image: circleci/ruby:2.6
-      - image: consul
-      - image: redis
-      - image: amazon/dynamodb-local
-  test-2.7:
-    <<: *ruby-docker-template
-    docker:
-      - image: circleci/ruby:2.7
-      - image: consul
-      - image: redis
-      - image: amazon/dynamodb-local
-  test-3.0:
-    <<: *ruby-docker-template
-    docker:
-      - image: circleci/ruby:3.0
-      - image: consul
-      - image: redis
-      - image: amazon/dynamodb-local
-  test-jruby-9.2:
-    <<: *ruby-docker-template
+  build-test-linux:
+    parameters:
+      docker-image:
+        type: string
+      jruby:
+        type: boolean
+        default: false
+
     docker:
-      - image: circleci/jruby:9.2-jdk
+      - image: <<parameters.docker-image>>
       - image: consul
       - image: redis
       - image: amazon/dynamodb-local
+
+    steps:
+      - checkout
+      - when:
+          condition: <<parameters.jruby>>
+          steps:
+            - run: gem install jruby-openssl  # required by bundler, no effect on Ruby MRI
+      - run: sudo apt-get update -y && sudo apt-get install -y build-essential
+      - run: ruby -v
+      - run: gem install bundler -v 2.2.10
+      - run: bundle _2.2.10_ install
+      - run: mkdir ./rspec
+      - run: bundle _2.2.10_ exec rspec --format progress --format RspecJunitFormatter -o ./rspec/rspec.xml spec
+      - store_test_results:
+          path: ./rspec
+      - store_artifacts:
+          path: ./rspec
diff --git a/launchdarkly-server-sdk.gemspec b/launchdarkly-server-sdk.gemspec
index dcf281fe..4321c874 100644
--- a/launchdarkly-server-sdk.gemspec
+++ b/launchdarkly-server-sdk.gemspec
@@ -22,7 +22,7 @@ Gem::Specification.new do |spec|
   spec.required_ruby_version = ">= 2.5.0"
 
   spec.add_development_dependency "aws-sdk-dynamodb", "~> 1.57"
-  spec.add_development_dependency "bundler", "~> 2.1"
+  spec.add_development_dependency "bundler", "2.2.10"
   spec.add_development_dependency "rspec", "~> 3.10"
   spec.add_development_dependency "diplomat", "~> 2.4.2"
   spec.add_development_dependency "redis", "~> 4.2"
@@ -36,10 +36,8 @@ Gem::Specification.new do |spec|
 
   spec.add_runtime_dependency "semantic", "~> 1.6"
   spec.add_runtime_dependency "concurrent-ruby", "~> 1.1"
-  spec.add_runtime_dependency "ld-eventsource", "~> 2.0"
+  spec.add_runtime_dependency "ld-eventsource", "2.0.1"
 
-  # lock json to 2.3.x as ruby libraries often remove
-  # support for older ruby versions in minor releases
-  spec.add_runtime_dependency "json", "~> 2.3.1"
-  spec.add_runtime_dependency "http", "~> 4.4.1"
+  spec.add_runtime_dependency "json", "~> 2.3"
+  spec.add_runtime_dependency "http", ">= 4.4.0", "< 6.0.0"
 end