diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,3 +1,9 @@
+## 3000.2.2.1
+
+- Special release which supports *only* `base >= 4.11`
+  (while 3000.2.2 supports `base < 4.11`) but is otherwise
+  morally the same as `xhtml-3000.2.2`.
+
 ## 3000.2.2
 
 - Add `Semigroup Html` instance
diff --git a/Text/XHtml/Internals.hs b/Text/XHtml/Internals.hs
--- a/Text/XHtml/Internals.hs
+++ b/Text/XHtml/Internals.hs
@@ -17,6 +17,7 @@
 
 import Data.Char
 import qualified Data.Semigroup as Sem
+import qualified Data.Monoid as Mon
 
 infixr 2 +++  -- combining Html
 infixr 7 <<   -- nesting Html
@@ -67,7 +68,7 @@
 instance Sem.Semigroup Html where
     (<>) = (+++)
 
-instance Sem.Monoid Html where
+instance Mon.Monoid Html where
     mempty = noHtml
     mappend = (Sem.<>)
 
diff --git a/xhtml.cabal b/xhtml.cabal
--- a/xhtml.cabal
+++ b/xhtml.cabal
@@ -1,5 +1,6 @@
+Cabal-version:      2.0
 Name:               xhtml
-Version:            3000.2.2
+Version:            3000.2.2.1
 Copyright:          Bjorn Bringert 2004-2006, Andy Gill and the Oregon
                     Graduate Institute of Science and Technology, 1999-2001
 Maintainer:         Chris Dornan <chris@chrisdornan.com>
@@ -15,7 +16,6 @@
 Homepage:           https://github.com/haskell/xhtml
 Bug-Reports:        https://github.com/haskell/xhtml/issues
 Build-type:         Simple
-Cabal-version:      >= 1.10
 extra-source-files: ChangeLog.md
 
 Source-repository head
@@ -27,7 +27,15 @@
     if impl(ghc >= 7.2)
         Default-Extensions: Safe
 
-    Build-depends: base >= 4 && < 5
+    -- We intentionally try to enlarge the configuration space only as little
+    -- as needed, thus we partition the space for the cabal solver into
+    --
+    --  - xhtml-3000.2.2   supports base  < 4.11 & cabal-version: 1.10
+    --  - xhtml-3000.2.2.1 supports base >= 4.11 & cabal-version: 2.0
+    --
+    -- as xhtml-3000.2.2 and xhtml-3000.2.2.1 are not distinguishable except
+    -- for their version number.
+    Build-depends: base >= 4.11 && < 5
     if impl(ghc >= 8.0)
         -- Enable warnings about potential future incompatibilities
         ghc-options: -Wcompat -Wnoncanonical-monadfail-instances -Wnoncanonical-monad-instances