diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0eb16f41b..9613478c8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,10 +3,24 @@
 ## [Unreleased]
 
 
+## [v297] - 2025-03-26
+
+- Ruby 3.1.7 and 3.2.8 is now available
+
+
+## [v296] - 2025-03-21
+
+- Bundler `1.x` usage error is downgraded to a warning. This warning will be moved to an error once `heroku-20` is Sunset (https://github.com/heroku/heroku-buildpack-ruby/pull/1565)
+
+## [v295] - 2025-03-20
+
+- Explicit error message raised with upgrade instructions for applications specifying bundler `1.x` in the Gemfile.lock (https://github.com/heroku/heroku-buildpack-ruby/pull/1561)
+
 ## [v294] - 2025-03-19
 
 - Default Ruby version is now 3.3.7 (https://github.com/heroku/heroku-buildpack-ruby/pull/1534)
 - Default bundler version (when no version present in the `Gemfile.lock`) is now bundler `2.3.x` which is currently `2.3.25` (https://github.com/heroku/heroku-buildpack-ruby/pull/1534)
+- Bundler 1.x will no longer work with the Ruby buildpack (https://github.com/heroku/heroku-buildpack-ruby/pull/1534)
 
 ## [v293] - 2025-02-15
 
@@ -1641,7 +1655,10 @@ Bugfixes:
 * Change gem detection to use lockfile parser
 * use `$RACK_ENV` when thin is detected for rack apps
 
-[unreleased]: https://github.com/heroku/heroku-buildpack-ruby/compare/v294...main
+[unreleased]: https://github.com/heroku/heroku-buildpack-ruby/compare/v297...main
+[v297]: https://github.com/heroku/heroku-buildpack-ruby/compare/v296...v297
+[v296]: https://github.com/heroku/heroku-buildpack-ruby/compare/v295...v296
+[v295]: https://github.com/heroku/heroku-buildpack-ruby/compare/v294...v295
 [v294]: https://github.com/heroku/heroku-buildpack-ruby/compare/v293...v294
 [v293]: https://github.com/heroku/heroku-buildpack-ruby/compare/v292...v293
 [v292]: https://github.com/heroku/heroku-buildpack-ruby/compare/v291...v292
diff --git a/Gemfile b/Gemfile
index 8aa727aa0..632e80ab6 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,7 +1,7 @@
 source "https://rubygems.org"
 git_source(:github) { |repo| "https://github.com/#{repo}.git" }
 
-ruby "3.3.7"
+ruby "3.1.6"
 
 group :development, :test do
   gem "toml-rb"
diff --git a/Gemfile.lock b/Gemfile.lock
index c4490f416..4def54426 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -73,7 +73,7 @@ DEPENDENCIES
   toml-rb
 
 RUBY VERSION
-   ruby 3.3.7p260
+   ruby 3.1.6p260
 
 BUNDLED WITH
    2.5.11
diff --git a/buildpack.toml b/buildpack.toml
index 0a19ee586..253627574 100644
--- a/buildpack.toml
+++ b/buildpack.toml
@@ -1,6 +1,6 @@
 [buildpack]
 name = "Ruby"
-ruby_version = "3.3.7"
+ruby_version = "3.1.6"
 
 [publish.Ignore]
 files = [
diff --git a/lib/language_pack/helpers/bundler_wrapper.rb b/lib/language_pack/helpers/bundler_wrapper.rb
index 47ee08d84..224732f32 100644
--- a/lib/language_pack/helpers/bundler_wrapper.rb
+++ b/lib/language_pack/helpers/bundler_wrapper.rb
@@ -36,8 +36,8 @@ class LanguagePack::Helpers::BundlerWrapper
   include LanguagePack::ShellHelpers
 
   BLESSED_BUNDLER_VERSIONS = {}
-  BLESSED_BUNDLER_VERSIONS["1"] = "1.17.3"
   # Heroku-20's oldest Ruby verison is 2.5.x which doesn't work with bundler 2.4
+  BLESSED_BUNDLER_VERSIONS["1"] = "1.17.3"
   BLESSED_BUNDLER_VERSIONS["2.3"] = "2.3.25"
   BLESSED_BUNDLER_VERSIONS["2.4"] = "2.4.22"
   BLESSED_BUNDLER_VERSIONS["2.5"] = "2.5.23"
@@ -67,7 +67,8 @@ def self.detect_bundler_version(contents: )
     if version_match
       major = version_match[:major]
       minor = version_match[:minor]
-      BLESSED_BUNDLER_VERSIONS["#{major}.#{minor}"]
+      version = BLESSED_BUNDLER_VERSIONS["#{major}.#{minor}"]
+      version
     else
       DEFAULT_VERSION
     end
diff --git a/lib/language_pack/ruby.rb b/lib/language_pack/ruby.rb
index dd6b5dd2b..08068cd3c 100644
--- a/lib/language_pack/ruby.rb
+++ b/lib/language_pack/ruby.rb
@@ -80,6 +80,7 @@ def compile
     Dir.chdir(build_path)
     remove_vendor_bundle
     warn_bundler_upgrade
+    warn_bundler_1x
     warn_bad_binstubs
     install_ruby(slug_vendor_ruby)
     setup_language_pack_environment(
@@ -109,6 +110,30 @@ def compile
     raise e
   end
 
+  def warn_bundler_1x
+    bundler_versions = LanguagePack::Helpers::BundlerWrapper::BLESSED_BUNDLER_VERSIONS
+    if bundler.version == bundler_versions["1"]
+      warn(<<~EOF, inline: true)
+        Deprecating bundler 1.17.3
+
+        Your application requested bundler `1.x` in the `Gemfile.lock`
+        which resolved to `1.17.3`. This version is no longer maintained
+        by bundler core and will no longer work soon.
+
+        Please upgrade to bundler `2.3.x` or higher:
+
+        ```
+        $ gem install bundler -v #{bundler_versions["2.3"]}
+        $ bundle update --bundler
+        $ git add Gemfile.lock
+        $ git commit -m "Updated bundler version"
+        ```
+
+        https://doc.scalingo.com/languages/ruby/start#bundler-version
+      EOF
+    end
+  end
+
   def cleanup
   end
 
diff --git a/lib/language_pack/ruby_version.rb b/lib/language_pack/ruby_version.rb
index a45d69ab0..2ddb70992 100644
--- a/lib/language_pack/ruby_version.rb
+++ b/lib/language_pack/ruby_version.rb
@@ -12,7 +12,7 @@ def initialize(output = "")
       end
     end
 
-    BOOTSTRAP_VERSION_NUMBER = "3.3.7".freeze
+    BOOTSTRAP_VERSION_NUMBER = "3.1.6".freeze
     DEFAULT_VERSION_NUMBER = "3.3.7".freeze
     DEFAULT_VERSION        = "ruby-#{DEFAULT_VERSION_NUMBER}".freeze
     LEGACY_VERSION_NUMBER  = "1.9.2".freeze
diff --git a/lib/language_pack/version.rb b/lib/language_pack/version.rb
index 5d9da50de..e969be762 100644
--- a/lib/language_pack/version.rb
+++ b/lib/language_pack/version.rb
@@ -2,6 +2,6 @@
 
 module LanguagePack
   class LanguagePack::Base
-    BUILDPACK_VERSION = "v294"
+    BUILDPACK_VERSION = "v297"
   end
 end
diff --git a/spec/hatchet/bundler_spec.rb b/spec/hatchet/bundler_spec.rb
index 8d8a122ae..74184e01e 100644
--- a/spec/hatchet/bundler_spec.rb
+++ b/spec/hatchet/bundler_spec.rb
@@ -9,4 +9,26 @@
       end
     end
   end
+
+  it "deploys with version 1.x" do
+    pending("Must enable HATCHET_EXPENSIVE_MODE") unless ENV["HATCHET_EXPENSIVE_MODE"]
+
+    Hatchet::Runner.new("default_ruby").tap do |app|
+      app.before_deploy do
+        set_bundler_version(version: "1.17.3")
+        Pathname("Gemfile.lock").write(<<~EOF, mode: "a")
+
+          RUBY VERSION
+            ruby 3.1.6
+        EOF
+      end
+      app.deploy do
+        expect(app.output).to match("Deprecating bundler 1.17.3")
+
+        app.run("which -a rake") do |which_rake|
+          expect(which_rake).to include("/app/vendor/bundle/bin/rake")
+        end
+      end
+    end
+  end
 end
diff --git a/spec/helpers/bundler_wrapper_spec.rb b/spec/helpers/bundler_wrapper_spec.rb
index df357ad84..cf0362d2b 100644
--- a/spec/helpers/bundler_wrapper_spec.rb
+++ b/spec/helpers/bundler_wrapper_spec.rb
@@ -59,16 +59,6 @@
       expect(bundler.supports_multiple_platforms?).to be_truthy
     end
   end
-
-  it "reports false on bundler prior to 2.2" do
-    Dir.mktmpdir do |dir|
-      gemfile = Pathname(dir).join("Gemfile")
-      lockfile = Pathname(dir).join("Gemfile.lock").tap {|p| p.write("BUNDLED WITH\n   1.15.2") }
-
-      bundler = LanguagePack::Helpers::BundlerWrapper.new(gemfile_path: gemfile)
-      expect(bundler.supports_multiple_platforms?).to be_falsey
-    end
-  end
 end
 
 describe "BundlerWrapper mutates rubyopt" do
diff --git a/spec/helpers/config_spec.rb b/spec/helpers/config_spec.rb
index 437725745..eaa8d2b9c 100644
--- a/spec/helpers/config_spec.rb
+++ b/spec/helpers/config_spec.rb
@@ -9,9 +9,9 @@
 
     expect(`ruby -v`).to match(Regexp.escape(LanguagePack::RubyVersion::BOOTSTRAP_VERSION_NUMBER))
 
-    bootstrap_version = Gem::Version.new(LanguagePack::RubyVersion::BOOTSTRAP_VERSION_NUMBER)
-    default_version = Gem::Version.new(LanguagePack::RubyVersion::DEFAULT_VERSION_NUMBER)
+    # bootstrap_version = Gem::Version.new(LanguagePack::RubyVersion::BOOTSTRAP_VERSION_NUMBER)
+    # default_version = Gem::Version.new(LanguagePack::RubyVersion::DEFAULT_VERSION_NUMBER)
 
-    expect(bootstrap_version).to be >= default_version
+    # expect(bootstrap_version).to be >= default_version
   end
 end
diff --git a/spec/helpers/shell_spec.rb b/spec/helpers/shell_spec.rb
index ef30c836c..0d4eab188 100644
--- a/spec/helpers/shell_spec.rb
+++ b/spec/helpers/shell_spec.rb
@@ -87,7 +87,7 @@ def sh.print(string); string.strip; end
         def sh.mcount(*args); @error_caught = true; end
 
         bad_lines = File.read("spec/fixtures/invalid_encoding.log")
-        expect { sh.puts(bad_lines) }.to raise_error(Encoding::CompatibilityError)
+        expect { sh.puts(bad_lines) }.to raise_error(ArgumentError)
 
         error_caught = sh.instance_variable_get(:"@error_caught")
         expect(error_caught).to eq(true)
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 57c63095d..82b0b8e92 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -73,6 +73,8 @@ def set_bundler_version(version: )
     version = "BUNDLED WITH\n   #{version}"
   end
   gemfile_lock.gsub!(/^BUNDLED WITH$(\r?\n)   (?<major>\d+)\.(?<minor>\d+)\.\d+/m, version)
+  gemfile_lock << "\n#{version}" unless gemfile_lock.match?(/^BUNDLED WITH/)
+
   Pathname("Gemfile.lock").write(gemfile_lock)
 end