diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,11 @@
 # Revision history for railroad
 
+## 0.1.1.1 -- 2026-02-28
+* Widen dependency bounds for better GHC compatibility:
+  - `base` → `>= 4.17 && < 4.23` (supports GHC 9.4 through 9.14)
+  - `effectful` → `>= 2.5 && < 2.7` (allows current 2.6.x series)
+  - `mtl` lower bound relaxed to `>= 2.2`
+
 ## 0.1.1.0 -- 2026-02-26
 * Add non unicode alias for `(?∅)`
 * Fix the fixity of `(??~)` to be inline with `(?~)`
diff --git a/railroad.cabal b/railroad.cabal
--- a/railroad.cabal
+++ b/railroad.cabal
@@ -1,6 +1,6 @@
 cabal-version:      3.0
 name:               railroad
-version:            0.1.1.0
+version:            0.1.1.1
 license:            BSD-3-Clause
 license-file:       LICENSE
 author:             Frederik Kallstrup Mastratisi
@@ -21,10 +21,10 @@
 common stuff
     ghc-options: -Wall
     build-depends:
-      base ^>=4.20.2.0,
-      effectful >= 2.5.1 && < 2.6,
-      mtl >= 2.3.1 && < 2.4,
-      validation >= 1.1.3 && < 1.2
+      base >=4.17 && < 4.23,
+      effectful >= 2.5 && < 2.7,
+      mtl >= 2.2 && < 2.4,
+      validation >= 1.1 && < 1.2
 
 library
     import:           stuff
@@ -43,6 +43,6 @@
     other-modules:    RailroadSpec
                       Railroad.MonadErrorSpec
     build-depends:
-                  base ^>=4.20.2.0,
+                  base  >=4.17 && < 4.23,
                   hspec  >= 2.11.14 && < 2.12,
                   railroad
diff --git a/src/Railroad.hs b/src/Railroad.hs
--- a/src/Railroad.hs
+++ b/src/Railroad.hs
@@ -87,7 +87,7 @@
 action ?~ defaultVal = action ??~ (const defaultVal)
 
 
--- TODO: Derive instances for it? Functor?
+-- | @IsEmpty@ or @TooMany ta@ — structurally a @Maybe ta@ for cardinality failures
 data CardinalityError ta = IsEmpty | TooMany !ta
 
 -- | Catamorphism for CardinalityError
diff --git a/src/Railroad/MonadError.hs b/src/Railroad/MonadError.hs
--- a/src/Railroad/MonadError.hs
+++ b/src/Railroad/MonadError.hs
@@ -24,14 +24,17 @@
          => (CErr f -> e) -> f -> m (CRes f)
 collapse toErr = either (throwError . toErr) pure . bifurcate
 
+-- | Collapses a structure using an error mapper.
 (??) :: forall a m e. (MonadError e m, Bifurcate a)
      => m a -> (CErr a -> e) -> m (CRes a)
 action ?? toErr = action >>= collapse toErr
 
+-- | Collapses a structure using an error mapper.
 (?) :: forall m e a. (MonadError e m, Bifurcate a)
     => m a -> e -> m (CRes a)
 action ? err = action ?? const err
 
+-- | Collapses any value based on a predicate
 (?>) :: forall m e a. (MonadError e m)
      => m a -> (a -> Bool) -> (a -> e) -> m a
 (?>) action predicate toErr = do
@@ -46,12 +49,14 @@
 (?~) :: forall m a. (Bifurcate a, Monad m) => m a -> CRes a -> m (CRes a)
 action ?~ defaultVal = action ??~ (const defaultVal)
 
+-- |  Non-empty is sucess state. Returns the collection as-is.
 (?+) :: forall m e t a. (MonadError e m, Foldable t)
      => m (t a) -> e -> m (t a)
 (?+) action err = do
   xs <- action
   if null xs then throwError err else pure xs
 
+-- | Single element is sucess state.  Returns the single element
 (?!) :: forall m e t a. (MonadError e m, Foldable t)
      => m (t a) -> (CardinalityError (t a) -> e) -> m a
 (?!) action toErr = do
@@ -61,6 +66,7 @@
     [x] -> pure x
     _   -> throwError $ toErr $ TooMany xs
 
+-- | Empty is success state. Returns Unit.
 (?∅) :: forall m e t a. (MonadError e m, Foldable t)
      => m (t a) -> (t a -> e) -> m ()
 (?∅) action toErr = do