diff --git a/Gemfile.lock b/Gemfile.lock
index ac08eb07..300ebb54 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -6,7 +6,7 @@ PATH
       parser (>= 3.3.0)
 
 GEM
-  remote: https://oss:Px2ENN7S91OmWaD5G7MIQJi1dmtmYrEh@gem.mutant.dev/
+  remote: https://gem.mutant.dev/
   specs:
     mutant-license (0.1.1.2.2355046999240944981729280251890364410689.5)
 
@@ -14,68 +14,70 @@ GEM
   remote: https://rubygems.org/
   specs:
     ast (2.4.2)
-    diff-lcs (1.5.0)
-    json (2.7.1)
+    diff-lcs (1.5.1)
+    json (2.7.2)
     language_server-protocol (3.17.0.3)
-    mutant (0.11.27)
+    mutant (0.12.1)
       diff-lcs (~> 1.3)
       parser (~> 3.3.0)
-      regexp_parser (~> 2.8.2)
+      regexp_parser (~> 2.9.0)
       sorbet-runtime (~> 0.5.0)
       unparser (~> 0.6.9)
-    mutant-rspec (0.11.27)
-      mutant (= 0.11.27)
+    mutant-rspec (0.12.1)
+      mutant (= 0.12.1)
       rspec-core (>= 3.8.0, < 4.0.0)
-    parallel (1.24.0)
-    parser (3.3.0.2)
+    parallel (1.25.1)
+    parser (3.3.2.0)
       ast (~> 2.4.1)
       racc
-    racc (1.7.3)
+    racc (1.8.0)
     rainbow (3.1.1)
-    regexp_parser (2.8.3)
-    rexml (3.2.6)
-    rspec (3.12.0)
-      rspec-core (~> 3.12.0)
-      rspec-expectations (~> 3.12.0)
-      rspec-mocks (~> 3.12.0)
-    rspec-core (3.12.2)
-      rspec-support (~> 3.12.0)
-    rspec-expectations (3.12.3)
+    regexp_parser (2.9.2)
+    rexml (3.2.9)
+      strscan
+    rspec (3.13.0)
+      rspec-core (~> 3.13.0)
+      rspec-expectations (~> 3.13.0)
+      rspec-mocks (~> 3.13.0)
+    rspec-core (3.13.0)
+      rspec-support (~> 3.13.0)
+    rspec-expectations (3.13.0)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.12.0)
+      rspec-support (~> 3.13.0)
     rspec-its (1.3.0)
       rspec-core (>= 3.0.0)
       rspec-expectations (>= 3.0.0)
-    rspec-mocks (3.12.6)
+    rspec-mocks (3.13.1)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.12.0)
-    rspec-support (3.12.1)
-    rubocop (1.59.0)
+      rspec-support (~> 3.13.0)
+    rspec-support (3.13.1)
+    rubocop (1.64.1)
       json (~> 2.3)
       language_server-protocol (>= 3.17.0)
       parallel (~> 1.10)
-      parser (>= 3.2.2.4)
+      parser (>= 3.3.0.2)
       rainbow (>= 2.2.2, < 4.0)
       regexp_parser (>= 1.8, < 3.0)
       rexml (>= 3.2.5, < 4.0)
-      rubocop-ast (>= 1.30.0, < 2.0)
+      rubocop-ast (>= 1.31.1, < 2.0)
       ruby-progressbar (~> 1.7)
       unicode-display_width (>= 2.4.0, < 3.0)
-    rubocop-ast (1.30.0)
-      parser (>= 3.2.1.0)
+    rubocop-ast (1.31.3)
+      parser (>= 3.3.1.0)
     rubocop-packaging (0.5.2)
       rubocop (>= 1.33, < 2.0)
     ruby-progressbar (1.13.0)
-    sorbet-runtime (0.5.11180)
+    sorbet-runtime (0.5.11422)
+    strscan (3.1.0)
     unicode-display_width (2.5.0)
 
 PLATFORMS
   ruby
 
 DEPENDENCIES
-  mutant (~> 0.11.27)
+  mutant (~> 0.12.1)
   mutant-license!
-  mutant-rspec (~> 0.11.27)
+  mutant-rspec (~> 0.12.1)
   rspec (~> 3.9)
   rspec-core (~> 3.9)
   rspec-its (~> 1.3.0)
@@ -84,4 +86,4 @@ DEPENDENCIES
   unparser!
 
 BUNDLED WITH
-   2.4.1
+   2.5.10
diff --git a/config/mutant.yml b/config/mutant.yml
index ef2279ab..981323ba 100644
--- a/config/mutant.yml
+++ b/config/mutant.yml
@@ -1,4 +1,5 @@
 ---
+usage: opensource
 includes:
 - lib
 integration: rspec
diff --git a/unparser.gemspec b/unparser.gemspec
index fc12e206..4a1404b5 100644
--- a/unparser.gemspec
+++ b/unparser.gemspec
@@ -28,8 +28,8 @@ Gem::Specification.new do |gem|
   gem.add_dependency('diff-lcs', '~> 1.3')
   gem.add_dependency('parser',   '>= 3.3.0')
 
-  gem.add_development_dependency('mutant',            '~> 0.11.27')
-  gem.add_development_dependency('mutant-rspec',      '~> 0.11.27')
+  gem.add_development_dependency('mutant',            '~> 0.12.1')
+  gem.add_development_dependency('mutant-rspec',      '~> 0.12.1')
   gem.add_development_dependency('rspec',             '~> 3.9')
   gem.add_development_dependency('rspec-core',        '~> 3.9')
   gem.add_development_dependency('rspec-its',         '~> 1.3.0')