diff --git a/Gemfile.lock b/Gemfile.lock
index e3154ffd59f..b386d23ea99 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -45,10 +45,10 @@ GEM
       rake (>= 10.4, < 14.0)
     ast (2.4.0)
     aws-eventstream (1.0.3)
-    aws-partitions (1.154.0)
-    aws-sdk-core (3.48.6)
+    aws-partitions (1.251.0)
+    aws-sdk-core (3.84.0)
       aws-eventstream (~> 1.0, >= 1.0.2)
-      aws-partitions (~> 1.0)
+      aws-partitions (~> 1, >= 1.239.0)
       aws-sigv4 (~> 1.1)
       jmespath (~> 1.0)
     aws-sdk-kms (1.17.0)
@@ -58,8 +58,8 @@ GEM
       aws-sdk-core (~> 3, >= 3.48.2)
       aws-sdk-kms (~> 1)
       aws-sigv4 (~> 1.0)
-    aws-sdk-sns (1.13.0)
-      aws-sdk-core (~> 3, >= 3.48.2)
+    aws-sdk-sns (1.21.0)
+      aws-sdk-core (~> 3, >= 3.71.0)
       aws-sigv4 (~> 1.1)
     aws-sigv4 (1.1.0)
       aws-eventstream (~> 1.0, >= 1.0.2)
diff --git a/spec/components/cooked_post_processor_spec.rb b/spec/components/cooked_post_processor_spec.rb
index f29701635b3..ea0a7147f4d 100644
--- a/spec/components/cooked_post_processor_spec.rb
+++ b/spec/components/cooked_post_processor_spec.rb
@@ -11,6 +11,7 @@ def s3_setup
   SiteSetting.s3_access_key_id = "s3-access-key-id"
   SiteSetting.s3_secret_access_key = "s3-secret-access-key"
   SiteSetting.s3_cdn_url = "https://s3.cdn.com"
+  SiteSetting.s3_region = "us-east-1"
   SiteSetting.enable_s3_uploads = true
   SiteSetting.authorized_extensions = "png|jpg|gif|mov|ogg|"
 end
@@ -504,11 +505,18 @@ describe CookedPostProcessor do
 
         context "s3_uploads" do
           before do
+            SiteSetting.s3_region = "us-east-1"
             s3_setup
             stored_path = Discourse.store.get_path_for_upload(upload)
             upload.update_column(:url, "#{SiteSetting.Upload.absolute_base_url}/#{stored_path}")
 
-            stub_request(:any, /some-bucket-on-s3\.s3\.amazonaws\.com/)
+            stub_request(:head, "https://#{SiteSetting.s3_upload_bucket}.s3.#{SiteSetting.s3_region}.amazonaws.com/")
+            stub_request(
+              :put,
+              "https://#{SiteSetting.s3_upload_bucket}.s3.#{SiteSetting.s3_region}.amazonaws.com/optimized/1X/#{upload.sha1}_2_#{optimized_size}.#{upload.extension}"
+            )
+
+            stub_request(:get, /#{SiteSetting.s3_upload_bucket}\.s3\.#{SiteSetting.s3_region}\.amazonaws\.com/)
 
             OptimizedImage.expects(:resize).returns(true)
             FileStore::BaseStore.any_instance.expects(:get_depth_for).returns(0)
@@ -519,8 +527,10 @@ describe CookedPostProcessor do
             upload.update_column(:secure, true)
           end
 
+          let(:optimized_size) { "600x500" }
+
           let(:post) do
-            Fabricate(:post, raw: "![large.png|600x500](#{upload.short_url})")
+            Fabricate(:post, raw: "![large.png|#{optimized_size}](#{upload.short_url})")
           end
 
           it "handles secure images with the correct lightbox link href" do
diff --git a/spec/components/file_store/base_store_spec.rb b/spec/components/file_store/base_store_spec.rb
index 13d0c36f8a5..7a32671077b 100644
--- a/spec/components/file_store/base_store_spec.rb
+++ b/spec/components/file_store/base_store_spec.rb
@@ -53,6 +53,7 @@ RSpec.describe FileStore::BaseStore do
       SiteSetting.s3_upload_bucket = "s3-upload-bucket"
       SiteSetting.s3_access_key_id = "some key"
       SiteSetting.s3_secret_access_key = "some secret key"
+      SiteSetting.s3_region = "us-east-1"
 
       stub_request(:get, upload_s3.url).to_return(status: 200, body: "Hello world")
     end
@@ -91,7 +92,7 @@ RSpec.describe FileStore::BaseStore do
       SiteSetting.login_required = true
       SiteSetting.secure_media = true
 
-      stub_request(:head, "https://s3-upload-bucket.s3.amazonaws.com/")
+      stub_request(:head, "https://s3-upload-bucket.s3.#{SiteSetting.s3_region}.amazonaws.com/")
       signed_url = Discourse.store.signed_url_for_path(upload_s3.url)
       stub_request(:get, signed_url).to_return(status: 200, body: "Hello world")
 
diff --git a/spec/components/post_creator_spec.rb b/spec/components/post_creator_spec.rb
index 547b38736d0..bef529fc30c 100644
--- a/spec/components/post_creator_spec.rb
+++ b/spec/components/post_creator_spec.rb
@@ -1400,13 +1400,14 @@ describe PostCreator do
       SiteSetting.s3_upload_bucket = "s3-upload-bucket"
       SiteSetting.s3_access_key_id = "some key"
       SiteSetting.s3_secret_access_key = "some secret key"
+      SiteSetting.s3_region = "us-east-1"
       SiteSetting.secure_media = true
 
-      stub_request(:head, "https://#{SiteSetting.s3_upload_bucket}.s3.amazonaws.com/")
+      stub_request(:head, "https://#{SiteSetting.s3_upload_bucket}.s3.#{SiteSetting.s3_region}.amazonaws.com/")
 
       stub_request(
         :put,
-        "https://#{SiteSetting.s3_upload_bucket}.s3.amazonaws.com/original/1X/#{image_upload.sha1}.#{image_upload.extension}?acl"
+        "https://#{SiteSetting.s3_upload_bucket}.s3.#{SiteSetting.s3_region}.amazonaws.com/original/1X/#{image_upload.sha1}.#{image_upload.extension}?acl"
       )
     end
 
diff --git a/spec/components/s3_helper_spec.rb b/spec/components/s3_helper_spec.rb
index 789c61a071e..a8a45865cbb 100644
--- a/spec/components/s3_helper_spec.rb
+++ b/spec/components/s3_helper_spec.rb
@@ -10,6 +10,7 @@ describe "S3Helper" do
     SiteSetting.enable_s3_uploads = true
     SiteSetting.s3_access_key_id = "abc"
     SiteSetting.s3_secret_access_key = "def"
+    SiteSetting.s3_region = "us-east-1"
 
     @lifecycle = <<~XML
       <?xml version="1.0" encoding="UTF-8"?>
@@ -40,10 +41,10 @@ describe "S3Helper" do
     stub_request(:get, "http://169.254.169.254/latest/meta-data/iam/security-credentials/").
       to_return(status: 404, body: "", headers: {})
 
-    stub_request(:get, "https://bob.s3.amazonaws.com/?lifecycle").
+    stub_request(:get, "https://bob.s3.#{SiteSetting.s3_region}.amazonaws.com/?lifecycle").
       to_return(status: 200, body: @lifecycle, headers: {})
 
-    stub_request(:put, "https://bob.s3.amazonaws.com/?lifecycle").
+    stub_request(:put, "https://bob.s3.#{SiteSetting.s3_region}.amazonaws.com/?lifecycle").
       with do |req|
 
       hash = Hash.from_xml(req.body.to_s)
diff --git a/spec/models/optimized_image_spec.rb b/spec/models/optimized_image_spec.rb
index 19ce996ef7b..f12f006d1c4 100644
--- a/spec/models/optimized_image_spec.rb
+++ b/spec/models/optimized_image_spec.rb
@@ -299,6 +299,7 @@ describe OptimizedImage do
         SiteSetting.s3_upload_bucket = "s3-upload-bucket"
         SiteSetting.s3_access_key_id = "some key"
         SiteSetting.s3_secret_access_key = "some secret key"
+        SiteSetting.s3_region = "us-east-1"
 
         tempfile = Tempfile.new(["discourse-external", ".png"])
 
@@ -328,12 +329,12 @@ describe OptimizedImage do
 
           stub_request(
             :head,
-            "https://#{SiteSetting.s3_upload_bucket}.s3.amazonaws.com/"
+            "https://#{SiteSetting.s3_upload_bucket}.s3.#{SiteSetting.s3_region}.amazonaws.com/"
           )
 
           stub_request(
             :put,
-            "https://#{SiteSetting.s3_upload_bucket}.s3.amazonaws.com#{optimized_path}"
+            "https://#{SiteSetting.s3_upload_bucket}.s3.#{SiteSetting.s3_region}.amazonaws.com#{optimized_path}"
           ).to_return(
             status: 200,
             headers: { "ETag" => "someetag" }
diff --git a/spec/models/post_spec.rb b/spec/models/post_spec.rb
index 72bf2cd0634..239771f7116 100644
--- a/spec/models/post_spec.rb
+++ b/spec/models/post_spec.rb
@@ -1326,19 +1326,20 @@ describe Post do
         SiteSetting.s3_upload_bucket = "s3-upload-bucket"
         SiteSetting.s3_access_key_id = "some key"
         SiteSetting.s3_secret_access_key = "some secret key"
+        SiteSetting.s3_region = "us-east-1"
         SiteSetting.secure_media = true
         attachment_upload.update!(original_filename: "hello.csv")
 
-        stub_request(:head, "https://#{SiteSetting.s3_upload_bucket}.s3.amazonaws.com/")
+        stub_request(:head, "https://#{SiteSetting.s3_upload_bucket}.s3.#{SiteSetting.s3_region}.amazonaws.com/")
 
         stub_request(
           :put,
-          "https://#{SiteSetting.s3_upload_bucket}.s3.amazonaws.com/original/1X/#{attachment_upload.sha1}.#{attachment_upload.extension}?acl"
+          "https://#{SiteSetting.s3_upload_bucket}.s3.#{SiteSetting.s3_region}.amazonaws.com/original/1X/#{attachment_upload.sha1}.#{attachment_upload.extension}?acl"
         )
 
         stub_request(
           :put,
-          "https://#{SiteSetting.s3_upload_bucket}.s3.amazonaws.com/original/1X/#{image_upload.sha1}.#{image_upload.extension}?acl"
+          "https://#{SiteSetting.s3_upload_bucket}.s3.#{SiteSetting.s3_region}.amazonaws.com/original/1X/#{image_upload.sha1}.#{image_upload.extension}?acl"
         )
       end
 
diff --git a/spec/models/topic_converter_spec.rb b/spec/models/topic_converter_spec.rb
index b439bf6c805..6259c13cfb1 100644
--- a/spec/models/topic_converter_spec.rb
+++ b/spec/models/topic_converter_spec.rb
@@ -112,13 +112,14 @@ describe TopicConverter do
           SiteSetting.s3_upload_bucket = "s3-upload-bucket"
           SiteSetting.s3_access_key_id = "some key"
           SiteSetting.s3_secret_access_key = "some secret key"
+          SiteSetting.s3_region = "us-east-1"
           SiteSetting.secure_media = true
 
-          stub_request(:head, "https://#{SiteSetting.s3_upload_bucket}.s3.amazonaws.com/")
+          stub_request(:head, "https://#{SiteSetting.s3_upload_bucket}.s3.#{SiteSetting.s3_region}.amazonaws.com/")
 
           stub_request(
             :put,
-            "https://#{SiteSetting.s3_upload_bucket}.s3.amazonaws.com/original/1X/#{image_upload.sha1}.#{image_upload.extension}?acl"
+            "https://#{SiteSetting.s3_upload_bucket}.s3.#{SiteSetting.s3_region}.amazonaws.com/original/1X/#{image_upload.sha1}.#{image_upload.extension}?acl"
           )
         end
 
diff --git a/spec/models/upload_spec.rb b/spec/models/upload_spec.rb
index 5d7cca2598a..e11f4b9102d 100644
--- a/spec/models/upload_spec.rb
+++ b/spec/models/upload_spec.rb
@@ -347,14 +347,15 @@ describe Upload do
         SiteSetting.enable_s3_uploads = true
         SiteSetting.s3_upload_bucket = "s3-upload-bucket"
         SiteSetting.s3_access_key_id = "some key"
-        SiteSetting.s3_secret_access_key = "some secret key"
+        SiteSetting.s3_secret_access_key = "some secrets3_region key"
+        SiteSetting.s3_region = "us-east-1"
         SiteSetting.secure_media = true
 
-        stub_request(:head, "https://#{SiteSetting.s3_upload_bucket}.s3.amazonaws.com/")
+        stub_request(:head, "https://#{SiteSetting.s3_upload_bucket}.s3.#{SiteSetting.s3_region}.amazonaws.com/")
 
         stub_request(
           :put,
-          "https://#{SiteSetting.s3_upload_bucket}.s3.amazonaws.com/original/1X/#{upload.sha1}.#{upload.extension}?acl"
+          "https://#{SiteSetting.s3_upload_bucket}.s3.#{SiteSetting.s3_region}.amazonaws.com/original/1X/#{upload.sha1}.#{upload.extension}?acl"
         )
       end
 
diff --git a/spec/requests/uploads_controller_spec.rb b/spec/requests/uploads_controller_spec.rb
index b70651d297a..b2d877d9f35 100644
--- a/spec/requests/uploads_controller_spec.rb
+++ b/spec/requests/uploads_controller_spec.rb
@@ -381,6 +381,7 @@ describe UploadsController do
         SiteSetting.s3_upload_bucket = "s3-upload-bucket"
         SiteSetting.s3_access_key_id = "fakeid7974664"
         SiteSetting.s3_secret_access_key = "fakesecretid7974664"
+        SiteSetting.s3_region = "us-east-1"
         SiteSetting.secure_media = true
       end
 
@@ -393,7 +394,7 @@ describe UploadsController do
       it "should return signed url for legitimate request" do
         secure_url = upload.url.sub(SiteSetting.Upload.absolute_base_url, "/secure-media-uploads")
         sign_in(user)
-        stub_request(:head, "https://s3-upload-bucket.s3.amazonaws.com/")
+        stub_request(:head, "https://#{SiteSetting.s3_upload_bucket}.s3.#{SiteSetting.s3_region}.amazonaws.com/")
 
         get secure_url