diff --git a/.ruby-version b/.ruby-version
index 57cf282..b0f6bf0 100644
--- a/.ruby-version
+++ b/.ruby-version
@@ -1 +1 @@
-2.6.5
+2.4.10
diff --git a/Gemfile b/Gemfile
index bf59941..e70ca81 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,6 +1,7 @@
 source "https://rubygems.org"
 
 gem "pg_query", ">= 1.0", "< 3"
+gem "bundler", "2.3.20"
 
 group :development do
   gem "rspec"
diff --git a/Gemfile.lock b/Gemfile.lock
index 8a8c3e7..2b59927 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -24,9 +24,10 @@ PLATFORMS
   ruby
 
 DEPENDENCIES
+  bundler (= 2.3.20)
   pg_query (>= 1.0, < 3)
   rake
   rspec
 
 BUNDLED WITH
-   2.4.2
+   2.3.20