diff --git a/CHANGELOG.md b/CHANGELOG.md
index 51c2031..2353d42 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+# 9.13.0
+
+* Add Slimmer::SourceWrapperNotFoundError to excluded exceptions.
+
 # 9.12.0
 
 * Set time_zone to London in all GOV.UK apps ([#381](/~https://github.com/alphagov/govuk_app_config/pull/381))
diff --git a/lib/govuk_app_config/govuk_error/configuration.rb b/lib/govuk_app_config/govuk_error/configuration.rb
index c1f5574..54e24d5 100644
--- a/lib/govuk_app_config/govuk_error/configuration.rb
+++ b/lib/govuk_app_config/govuk_error/configuration.rb
@@ -45,6 +45,7 @@ def set_up_defaults
         "Puma::HttpParserError",
         "Sinatra::NotFound",
         "Slimmer::IntermittentRetrievalError",
+        "Slimmer::SourceWrapperNotFoundError",
         "Sidekiq::JobRetry::Skip",
         "SignalException",
       ]
diff --git a/lib/govuk_app_config/version.rb b/lib/govuk_app_config/version.rb
index f2d8063..62e79d8 100644
--- a/lib/govuk_app_config/version.rb
+++ b/lib/govuk_app_config/version.rb
@@ -1,3 +1,3 @@
 module GovukAppConfig
-  VERSION = "9.12.0".freeze
+  VERSION = "9.13.0".freeze
 end