diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index e99ab82..aa5d164 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -26,9 +26,9 @@ jobs:
       github.repository == 'stainless-sdks/imagekit-ruby' &&
       (github.event_name == 'push' || github.event.pull_request.head.repo.fork) && (github.event_name != 'push' || github.event.head_commit.message != 'codegen metadata')
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
       - name: Set up Ruby
-        uses: ruby/setup-ruby@v1
+        uses: ruby/setup-ruby@c4e5b1316158f92e3d49443a9d58b31d25ac0f8f # v1.306.0
         with:
           bundler-cache: false
       - run: |-
@@ -39,7 +39,7 @@ jobs:
           github.repository == 'stainless-sdks/imagekit-ruby' &&
           !startsWith(github.ref, 'refs/heads/stl/')
         id: github-oidc
-        uses: actions/github-script@v8
+        uses: actions/github-script@ed597411d8f924073f98dfc5c65a23a2325f34cd # v8.0.0
         with:
           script: core.setOutput('github_token', await core.getIDToken());
 
@@ -60,9 +60,9 @@ jobs:
     if: github.event_name == 'push' || github.event.pull_request.head.repo.fork
 
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
       - name: Set up Ruby
-        uses: ruby/setup-ruby@v1
+        uses: ruby/setup-ruby@c4e5b1316158f92e3d49443a9d58b31d25ac0f8f # v1.306.0
         with:
           bundler-cache: false
       - run: |-
@@ -76,9 +76,9 @@ jobs:
     runs-on: ${{ github.repository == 'stainless-sdks/imagekit-ruby' && 'depot-ubuntu-24.04' || 'ubuntu-latest' }}
     if: github.event_name == 'push' || github.event.pull_request.head.repo.fork
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
       - name: Set up Ruby
-        uses: ruby/setup-ruby@v1
+        uses: ruby/setup-ruby@c4e5b1316158f92e3d49443a9d58b31d25ac0f8f # v1.306.0
         with:
           bundler-cache: false
       - run: |-
diff --git a/.github/workflows/publish-gem.yml b/.github/workflows/publish-gem.yml
index 642e1eb..dc4f30c 100644
--- a/.github/workflows/publish-gem.yml
+++ b/.github/workflows/publish-gem.yml
@@ -14,9 +14,9 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
       - name: Set up Ruby
-        uses: ruby/setup-ruby@v1
+        uses: ruby/setup-ruby@c4e5b1316158f92e3d49443a9d58b31d25ac0f8f # v1.306.0
         with:
           bundler-cache: false
       - run: |-
diff --git a/.github/workflows/release-doctor.yml b/.github/workflows/release-doctor.yml
index 26014cc..bd2fe0e 100644
--- a/.github/workflows/release-doctor.yml
+++ b/.github/workflows/release-doctor.yml
@@ -12,7 +12,7 @@ jobs:
     if: github.repository == 'imagekit-developer/imagekit-ruby' && (github.event_name == 'push' || github.event_name == 'workflow_dispatch' || startsWith(github.head_ref, 'release-please') || github.head_ref == 'next')
 
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
 
       - name: Check release environment
         run: |
diff --git a/.release-please-manifest.json b/.release-please-manifest.json
index 396d9f0..3d5f4e3 100644
--- a/.release-please-manifest.json
+++ b/.release-please-manifest.json
@@ -1,3 +1,3 @@
 {
-  ".": "4.4.1"
+  ".": "4.5.0"
 }
\ No newline at end of file
diff --git a/.stats.yml b/.stats.yml
index a1b609a..278a536 100644
--- a/.stats.yml
+++ b/.stats.yml
@@ -1,4 +1,4 @@
 configured_endpoints: 47
-openapi_spec_url: https://storage.googleapis.com/stainless-sdk-openapi-specs/imagekit-inc%2Fimagekit-c7f578172392bde58bbb72be2a25b9e917529cd07550358c645ce155debf2418.yml
-openapi_spec_hash: f0d797a17b1e8e81707517700cd44b13
+openapi_spec_url: https://storage.googleapis.com/stainless-sdk-openapi-specs/imagekit-inc/imagekit-ad6dd3b4acf289708568a12574b997503059a47c4a4ca5ffefe64f40f3d3dbf3.yml
+openapi_spec_hash: 7c103e2dff0edcbeea82057e62f58d4d
 config_hash: 94f48fd13b7d41b8b6a203a3a8cee9ed
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 63354d3..8ccadc4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,20 @@
 # Changelog
 
+## 4.5.0 (2026-05-13)
+
+Full Changelog: [v4.4.1...v4.5.0](https://github.com/imagekit-developer/imagekit-ruby/compare/v4.4.1...v4.5.0)
+
+### Features
+
+* **api:** add no-enlarge crop modes and colorize transformation ([1b56303](https://github.com/imagekit-developer/imagekit-ruby/commit/1b56303ef5c67cb1a4b36d4a1c06b147f22c5987))
+* support setting headers via env ([cd32783](https://github.com/imagekit-developer/imagekit-ruby/commit/cd32783efe49d795b8a5de49eb44039cda375d2e))
+* **transformation:** add colorize transformation support in URL generation ([3454064](https://github.com/imagekit-developer/imagekit-ruby/commit/34540646f7ee8a1deabeea629f366d28bc71f734))
+
+
+### Chores
+
+* **internal:** codegen related update ([7e0543d](https://github.com/imagekit-developer/imagekit-ruby/commit/7e0543d8714ff251de1a32f471dc7bd8bfa17dab))
+
 ## 4.4.1 (2026-04-24)
 
 Full Changelog: [v4.4.0...v4.4.1](https://github.com/imagekit-developer/imagekit-ruby/compare/v4.4.0...v4.4.1)
diff --git a/Gemfile.lock b/Gemfile.lock
index d8e6b57..088e705 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -11,7 +11,7 @@ GIT
 PATH
   remote: .
   specs:
-    imagekitio (4.4.1)
+    imagekitio (4.5.0)
       cgi
       connection_pool
       standardwebhooks
@@ -144,7 +144,7 @@ GEM
       rexml (>= 3.2.6)
       sorbet-static-and-runtime (>= 0.5.10187)
       thor (>= 0.19.2)
-    standardwebhooks (1.0.1)
+    standardwebhooks (1.1.0)
     steep (1.10.0)
       activesupport (>= 5.1)
       concurrent-ruby (>= 1.1.10)
diff --git a/README.md b/README.md
index 8c8e0ba..7a03c78 100644
--- a/README.md
+++ b/README.md
@@ -46,7 +46,7 @@ To use this gem, install via Bundler by adding the following to your application
 <!-- x-release-please-start-version -->
 
 ```ruby
-gem "imagekitio", "~> 4.4.1"
+gem "imagekitio", "~> 4.5.0"
 ```
 
 <!-- x-release-please-end -->
diff --git a/lib/imagekitio/client.rb b/lib/imagekitio/client.rb
index dc6d989..b4bfd22 100644
--- a/lib/imagekitio/client.rb
+++ b/lib/imagekitio/client.rb
@@ -120,6 +120,19 @@ def initialize(
         raise ArgumentError.new("private_key is required, and can be set via environ: \"IMAGEKIT_PRIVATE_KEY\"")
       end
 
+      headers = {}
+      custom_headers_env = ENV["IMAGE_KIT_CUSTOM_HEADERS"]
+      unless custom_headers_env.nil?
+        parsed = {}
+        custom_headers_env.split("\n").each do |line|
+          colon = line.index(":")
+          unless colon.nil?
+            parsed[line[0...colon].strip] = line[(colon + 1)..].strip
+          end
+        end
+        headers = parsed.merge(headers)
+      end
+
       @private_key = private_key.to_s
       @password = password.to_s
       @webhook_secret = webhook_secret&.to_s
@@ -129,7 +142,8 @@ def initialize(
         timeout: timeout,
         max_retries: max_retries,
         initial_retry_delay: initial_retry_delay,
-        max_retry_delay: max_retry_delay
+        max_retry_delay: max_retry_delay,
+        headers: headers
       )
 
       @custom_metadata_fields = Imagekitio::Resources::CustomMetadataFields.new(client: self)
diff --git a/lib/imagekitio/helpers/transformation_utils.rb b/lib/imagekitio/helpers/transformation_utils.rb
index 45c02a0..03a385b 100644
--- a/lib/imagekitio/helpers/transformation_utils.rb
+++ b/lib/imagekitio/helpers/transformation_utils.rb
@@ -84,6 +84,7 @@ module TransformationUtils
       "gradient" => "e-gradient",
       "color_replace" => "cr",
       "colorReplace" => "cr",
+      "colorize" => "e-colorize",
       "distort" => "e-distort",
 
       # Other flags & finishing
diff --git a/lib/imagekitio/models/transformation.rb b/lib/imagekitio/models/transformation.rb
index 160d809..4e41bbd 100644
--- a/lib/imagekitio/models/transformation.rb
+++ b/lib/imagekitio/models/transformation.rb
@@ -138,6 +138,18 @@ class Transformation < Imagekitio::Internal::Type::BaseModel
       #   @return [String, nil]
       optional :border, String
 
+      # @!attribute colorize
+      #   Applies a color tint to the image. Accepts color and intensity as optional
+      #   parameters.
+      #
+      #   - `co-color` - Color to apply (e.g., `red`, `blue`, `FF0022`). Default is gray
+      #     color.
+      #   - `in-intensity` - Intensity of the color (0-100). Default is 35. See
+      #     [Colorize](https://imagekit.io/docs/effects-and-enhancements#colorize---e-colorize).
+      #
+      #   @return [String, nil]
+      optional :colorize, String
+
       # @!attribute color_profile
       #   Indicates whether the output image should retain the original color profile. See
       #   [Color profile](https://imagekit.io/docs/image-optimization#color-profile---cp).
@@ -498,7 +510,7 @@ class Transformation < Imagekitio::Internal::Type::BaseModel
       #   @return [Float, nil]
       optional :zoom, Float
 
-      # @!method initialize(ai_change_background: nil, ai_drop_shadow: nil, ai_edit: nil, ai_remove_background: nil, ai_remove_background_external: nil, ai_retouch: nil, ai_upscale: nil, ai_variation: nil, aspect_ratio: nil, audio_codec: nil, background: nil, blur: nil, border: nil, color_profile: nil, color_replace: nil, contrast_stretch: nil, crop: nil, crop_mode: nil, default_image: nil, distort: nil, dpr: nil, duration: nil, end_offset: nil, flip: nil, focus: nil, format_: nil, gradient: nil, grayscale: nil, height: nil, lossless: nil, metadata: nil, named: nil, opacity: nil, original: nil, overlay: nil, page: nil, progressive: nil, quality: nil, radius: nil, raw: nil, rotation: nil, shadow: nil, sharpen: nil, start_offset: nil, streaming_resolutions: nil, trim: nil, unsharp_mask: nil, video_codec: nil, width: nil, x: nil, x_center: nil, y_: nil, y_center: nil, zoom: nil)
+      # @!method initialize(ai_change_background: nil, ai_drop_shadow: nil, ai_edit: nil, ai_remove_background: nil, ai_remove_background_external: nil, ai_retouch: nil, ai_upscale: nil, ai_variation: nil, aspect_ratio: nil, audio_codec: nil, background: nil, blur: nil, border: nil, colorize: nil, color_profile: nil, color_replace: nil, contrast_stretch: nil, crop: nil, crop_mode: nil, default_image: nil, distort: nil, dpr: nil, duration: nil, end_offset: nil, flip: nil, focus: nil, format_: nil, gradient: nil, grayscale: nil, height: nil, lossless: nil, metadata: nil, named: nil, opacity: nil, original: nil, overlay: nil, page: nil, progressive: nil, quality: nil, radius: nil, raw: nil, rotation: nil, shadow: nil, sharpen: nil, start_offset: nil, streaming_resolutions: nil, trim: nil, unsharp_mask: nil, video_codec: nil, width: nil, x: nil, x_center: nil, y_: nil, y_center: nil, zoom: nil)
       #   Some parameter documentations has been truncated, see
       #   {Imagekitio::Models::Transformation} for more details.
       #
@@ -535,6 +547,8 @@ class Transformation < Imagekitio::Internal::Type::BaseModel
       #
       #   @param border [String] Adds a border to the output media. Accepts a string in the format `<border-width
       #
+      #   @param colorize [String] Applies a color tint to the image. Accepts color and intensity as optional param
+      #
       #   @param color_profile [Boolean] Indicates whether the output image should retain the original color profile.
       #
       #   @param color_replace [String] Replaces colors in the image. Supports three formats:
@@ -765,6 +779,7 @@ module Crop
         AT_MAX_ENLARGE = :at_max_enlarge
         AT_LEAST = :at_least
         MAINTAIN_RATIO = :maintain_ratio
+        MAINTAIN_RATIO_NO_ENLARGE = :maintain_ratio_no_enlarge
 
         # @!method self.values
         #   @return [Array<Symbol>]
@@ -780,6 +795,8 @@ module CropMode
         PAD_RESIZE = :pad_resize
         EXTRACT = :extract
         PAD_EXTRACT = :pad_extract
+        PAD_RESIZE_NO_ENLARGE = :pad_resize_no_enlarge
+        PAD_EXTRACT_NO_SHRINK = :pad_extract_no_shrink
 
         # @!method self.values
         #   @return [Array<Symbol>]
diff --git a/lib/imagekitio/version.rb b/lib/imagekitio/version.rb
index 4f6f300..fd555c9 100644
--- a/lib/imagekitio/version.rb
+++ b/lib/imagekitio/version.rb
@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module Imagekitio
-  VERSION = "4.4.1"
+  VERSION = "4.5.0"
 end
diff --git a/rbi/imagekitio/models/transformation.rbi b/rbi/imagekitio/models/transformation.rbi
index 607451a..ffb8de7 100644
--- a/rbi/imagekitio/models/transformation.rbi
+++ b/rbi/imagekitio/models/transformation.rbi
@@ -198,6 +198,19 @@ module Imagekitio
       sig { params(border: String).void }
       attr_writer :border
 
+      # Applies a color tint to the image. Accepts color and intensity as optional
+      # parameters.
+      #
+      # - `co-color` - Color to apply (e.g., `red`, `blue`, `FF0022`). Default is gray
+      #   color.
+      # - `in-intensity` - Intensity of the color (0-100). Default is 35. See
+      #   [Colorize](https://imagekit.io/docs/effects-and-enhancements#colorize---e-colorize).
+      sig { returns(T.nilable(String)) }
+      attr_reader :colorize
+
+      sig { params(colorize: String).void }
+      attr_writer :colorize
+
       # Indicates whether the output image should retain the original color profile. See
       # [Color profile](https://imagekit.io/docs/image-optimization#color-profile---cp).
       sig { returns(T.nilable(T::Boolean)) }
@@ -664,6 +677,7 @@ module Imagekitio
           background: String,
           blur: Float,
           border: String,
+          colorize: String,
           color_profile: T::Boolean,
           color_replace: String,
           contrast_stretch:
@@ -785,6 +799,14 @@ module Imagekitio
         # expression like `ih_div_20_FF00FF`. See
         # [Border](https://imagekit.io/docs/effects-and-enhancements#border---b).
         border: nil,
+        # Applies a color tint to the image. Accepts color and intensity as optional
+        # parameters.
+        #
+        # - `co-color` - Color to apply (e.g., `red`, `blue`, `FF0022`). Default is gray
+        #   color.
+        # - `in-intensity` - Intensity of the color (0-100). Default is 35. See
+        #   [Colorize](https://imagekit.io/docs/effects-and-enhancements#colorize---e-colorize).
+        colorize: nil,
         # Indicates whether the output image should retain the original color profile. See
         # [Color profile](https://imagekit.io/docs/image-optimization#color-profile---cp).
         color_profile: nil,
@@ -998,6 +1020,7 @@ module Imagekitio
             background: String,
             blur: Float,
             border: String,
+            colorize: String,
             color_profile: T::Boolean,
             color_replace: String,
             contrast_stretch:
@@ -1285,6 +1308,11 @@ module Imagekitio
           T.let(:at_least, Imagekitio::Transformation::Crop::TaggedSymbol)
         MAINTAIN_RATIO =
           T.let(:maintain_ratio, Imagekitio::Transformation::Crop::TaggedSymbol)
+        MAINTAIN_RATIO_NO_ENLARGE =
+          T.let(
+            :maintain_ratio_no_enlarge,
+            Imagekitio::Transformation::Crop::TaggedSymbol
+          )
 
         sig do
           override.returns(
@@ -1313,6 +1341,16 @@ module Imagekitio
             :pad_extract,
             Imagekitio::Transformation::CropMode::TaggedSymbol
           )
+        PAD_RESIZE_NO_ENLARGE =
+          T.let(
+            :pad_resize_no_enlarge,
+            Imagekitio::Transformation::CropMode::TaggedSymbol
+          )
+        PAD_EXTRACT_NO_SHRINK =
+          T.let(
+            :pad_extract_no_shrink,
+            Imagekitio::Transformation::CropMode::TaggedSymbol
+          )
 
         sig do
           override.returns(
diff --git a/sig/imagekitio/models/transformation.rbs b/sig/imagekitio/models/transformation.rbs
index 80be008..4124021 100644
--- a/sig/imagekitio/models/transformation.rbs
+++ b/sig/imagekitio/models/transformation.rbs
@@ -15,6 +15,7 @@ module Imagekitio
         background: String,
         blur: Float,
         border: String,
+        colorize: String,
         color_profile: bool,
         color_replace: String,
         contrast_stretch: Imagekitio::Models::Transformation::contrast_stretch,
@@ -127,6 +128,10 @@ module Imagekitio
 
       def border=: (String) -> String
 
+      attr_reader colorize: String?
+
+      def colorize=: (String) -> String
+
       attr_reader color_profile: bool?
 
       def color_profile=: (bool) -> bool
@@ -355,6 +360,7 @@ module Imagekitio
         ?background: String,
         ?blur: Float,
         ?border: String,
+        ?colorize: String,
         ?color_profile: bool,
         ?color_replace: String,
         ?contrast_stretch: Imagekitio::Models::Transformation::contrast_stretch,
@@ -412,6 +418,7 @@ module Imagekitio
         background: String,
         blur: Float,
         border: String,
+        colorize: String,
         color_profile: bool,
         color_replace: String,
         contrast_stretch: Imagekitio::Models::Transformation::contrast_stretch,
@@ -544,7 +551,12 @@ module Imagekitio
       end
 
       type crop =
-        :force | :at_max | :at_max_enlarge | :at_least | :maintain_ratio
+        :force
+        | :at_max
+        | :at_max_enlarge
+        | :at_least
+        | :maintain_ratio
+        | :maintain_ratio_no_enlarge
 
       module Crop
         extend Imagekitio::Internal::Type::Enum
@@ -554,11 +566,17 @@ module Imagekitio
         AT_MAX_ENLARGE: :at_max_enlarge
         AT_LEAST: :at_least
         MAINTAIN_RATIO: :maintain_ratio
+        MAINTAIN_RATIO_NO_ENLARGE: :maintain_ratio_no_enlarge
 
         def self?.values: -> ::Array[Imagekitio::Models::Transformation::crop]
       end
 
-      type crop_mode = :pad_resize | :extract | :pad_extract
+      type crop_mode =
+        :pad_resize
+        | :extract
+        | :pad_extract
+        | :pad_resize_no_enlarge
+        | :pad_extract_no_shrink
 
       module CropMode
         extend Imagekitio::Internal::Type::Enum
@@ -566,6 +584,8 @@ module Imagekitio
         PAD_RESIZE: :pad_resize
         EXTRACT: :extract
         PAD_EXTRACT: :pad_extract
+        PAD_RESIZE_NO_ENLARGE: :pad_resize_no_enlarge
+        PAD_EXTRACT_NO_SHRINK: :pad_extract_no_shrink
 
         def self?.values: -> ::Array[Imagekitio::Models::Transformation::crop_mode]
       end
diff --git a/test/imagekitio/custom-tests/url-generation/advanced_url_generation_test.rb b/test/imagekitio/custom-tests/url-generation/advanced_url_generation_test.rb
index aa8298a..2a2d835 100644
--- a/test/imagekitio/custom-tests/url-generation/advanced_url_generation_test.rb
+++ b/test/imagekitio/custom-tests/url-generation/advanced_url_generation_test.rb
@@ -434,6 +434,7 @@ def test_should_generate_the_correct_url_with_many_transformations_including_vid
         # New transformations
         color_replace: "FF0000_50_0000FF",
         distort: "p-100_50_200_150_300_250_400_350",
+        colorize: "co-FF0000_in-15",
         original: true,
         page: "2_4",
         raw: "h-200,w-300,l-image,i-logo.png,l-end"
@@ -449,7 +450,7 @@ def test_should_generate_the_correct_url_with_many_transformations_including_vid
       )
     )
 
-    expected = "https://ik.imagekit.io/test_url_endpoint/test_path.jpg?tr=h-300,w-400,ar-4-3,q-40,c-force,cm-extract,fo-left,f-jpeg,r-50,bg-A94D34,b-5-A94D34,rt-90,bl-10,n-some_name,pr-true,lo-true,t-5,md-true,cp-true,di-folder@@file.jpg,dpr-3,x-10,y-20,xc-30,yc-40,fl-h,o-0.8,z-2,vc-h264,ac-aac,so-5,eo-15,du-10,sr-1440_1080,e-grayscale,e-upscale,e-retouch,e-genvar,e-dropshadow,e-changebg-prompt-car,e-edit-prompt-make it vintage,e-bgremove,e-contrast,e-shadow-bl-15_st-40_x-10_y-N5,e-sharpen-10,e-usm-2-2-0.8-0.024,e-gradient-from-red_to-white,cr-FF0000_50_0000FF,e-distort-p-100_50_200_150_300_250_400_350,orig-true,pg-2_4,h-200,w-300,l-image,i-logo.png,l-end"
+    expected = "https://ik.imagekit.io/test_url_endpoint/test_path.jpg?tr=h-300,w-400,ar-4-3,q-40,c-force,cm-extract,fo-left,f-jpeg,r-50,bg-A94D34,b-5-A94D34,rt-90,bl-10,n-some_name,pr-true,lo-true,t-5,md-true,cp-true,di-folder@@file.jpg,dpr-3,x-10,y-20,xc-30,yc-40,fl-h,o-0.8,z-2,vc-h264,ac-aac,so-5,eo-15,du-10,sr-1440_1080,e-grayscale,e-upscale,e-retouch,e-genvar,e-dropshadow,e-changebg-prompt-car,e-edit-prompt-make it vintage,e-bgremove,e-contrast,e-shadow-bl-15_st-40_x-10_y-N5,e-sharpen-10,e-usm-2-2-0.8-0.024,e-gradient-from-red_to-white,cr-FF0000_50_0000FF,e-distort-p-100_50_200_150_300_250_400_350,e-colorize-co-FF0000_in-15,orig-true,pg-2_4,h-200,w-300,l-image,i-logo.png,l-end"
     assert_equal(expected, url)
   end