diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index a03d513..58e84ad 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -17,6 +17,8 @@ tests:
     matrix:
       - RUBY_VERSION: ['3.0', '3.1', '3.2', '3.3']
   before_script:
+    - gem sources --remove https://rubygems.org/
+    - gem sources --add ${NEXUS_PUBLIC_SOURCE_URL}
     - bin/setup
   script:
     - bundle exec appraisal rspec --format RspecJunitFormatter --out test-results/rspec_$RUBY_VERSION.xml --format documentation
diff --git a/CHANGELOG.md b/CHANGELOG.md
index e725b29..6927510 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,6 +13,12 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ### Fixed
 
+## [3.1.1] - 2024-10-31
+
+### Changed
+
+- Update README
+
 ## [3.1.0] - 2024-09-13
 
 ### Added
diff --git a/Gemfile b/Gemfile
index be173b2..f1c034f 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
-source "https://rubygems.org"
+source ENV.fetch("NEXUS_PUBLIC_SOURCE_URL", "https://rubygems.org")
 
 gemspec
diff --git a/README.md b/README.md
index 1ab773c..378c69b 100644
--- a/README.md
+++ b/README.md
@@ -66,7 +66,7 @@ default: &default
   # see more options at https://github.com/karafka/waterdrop/blob/master/lib/waterdrop/config.rb
   wait_on_queue_full: true
   max_payload_size: 1000012
-  max_wait_timeout_ms: 60000
+  max_wait_timeout: 60000
   auth:
     kind: plaintext
   kafka:
@@ -77,9 +77,9 @@ default: &default
     retry_backoff: 1000 # in milliseconds, optional, default: 1000
     connect_timeout: 2000 # in milliseconds, optional, default: 2000
     message_timeout: 55000 # in milliseconds, optional, default: 55000
-    kafka_config: # low-level custom Kafka options
-      queue.buffering.max.messages: 1
-      queue.buffering.max.ms: 10000
+    # kafka_config: # optional, low-level custom Kafka options (see https://github.com/confluentinc/librdkafka/blob/master/CONFIGURATION.md)
+    #   queue.buffering.max.messages: 100000
+    #   queue.buffering.max.ms: 5
 
 development:
   <<: *default
diff --git a/lib/sbmt/kafka_producer/version.rb b/lib/sbmt/kafka_producer/version.rb
index 8eab7f3..59fde92 100644
--- a/lib/sbmt/kafka_producer/version.rb
+++ b/lib/sbmt/kafka_producer/version.rb
@@ -2,6 +2,6 @@
 
 module Sbmt
   module KafkaProducer
-    VERSION = "3.1.0"
+    VERSION = "3.1.1"
   end
 end