diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,4 +1,12 @@
 
+6.6
+---
+
+* Added support for horizontal scrolling inputs. The `Button` type in
+  `Graphics.Vty.Input.Events` got new constructors `BScrollLeft` and
+  `BScrollRight` for Vty backend implementations that support horizontal
+  scrolling inputs.
+
 6.5
 ---
 
diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -148,14 +148,18 @@
 If you decide to contribute, that's great! Here are some guidelines you
 should consider to make submitting patches easier for all concerned:
 
- - Please ensure that the examples and test suites build along with the
-   library by running `build.sh` in the repository.
+ - Patches written completely or partially by AI are unlikely to be
+   accepted. Please disclose any AI use.
  - If you want to take on big things, talk to me first; let's have a
    design/vision discussion before you start coding. Create a GitHub
    issue and we can use that as the place to hash things out.
  - If you make changes, make them consistent with the syntactic
    conventions already used in the codebase.
  - Please provide Haddock documentation for any changes you make.
+ - Please do NOT include package version changes in your patches.
+   Package version changes are only done at release time when the full
+   scope of a release's changes can be evaluated to determine the
+   appropriate version change.
 
 # Further Reading
 
diff --git a/src/Graphics/Vty/Input/Events.hs b/src/Graphics/Vty/Input/Events.hs
--- a/src/Graphics/Vty/Input/Events.hs
+++ b/src/Graphics/Vty/Input/Events.hs
@@ -42,7 +42,16 @@
 instance NFData Modifier
 
 -- | Mouse buttons.
-data Button = BLeft | BMiddle | BRight | BScrollUp | BScrollDown
+data Button
+    = BLeft
+    | BMiddle
+    | BRight
+    | BScrollUp
+    | BScrollDown
+    | BScrollLeft
+    -- ^ Some terminals (e.g., Kitty, Alacritty) support horizontal
+    -- scrolling in addition to vertical scrolling.
+    | BScrollRight
     deriving (Eq, Show, Read, Ord, Generic)
 
 instance NFData Button
diff --git a/vty.cabal b/vty.cabal
--- a/vty.cabal
+++ b/vty.cabal
@@ -1,5 +1,5 @@
 name:                vty
-version:             6.5
+version:             6.6
 license:             BSD3
 license-file:        LICENSE
 author:              AUTHORS