diff --git a/doc/cabal-project-description-file.rst b/doc/cabal-project-description-file.rst
index 4b3858862f4..b9063a5a37b 100644
--- a/doc/cabal-project-description-file.rst
+++ b/doc/cabal-project-description-file.rst
@@ -1838,16 +1838,19 @@ running ``setup haddock``.
 
     :default: False
 
-    Generated hyperlinked source code using `HsColour`_, and have
-    Haddock documentation link to it.
+    Generate hyperlinked source code and have Haddock documentation
+    link to it.
     This is equivalent to running ``haddock`` with the ``--hyperlinked-source`` flag.
+    Haddock versions older than 2.17 don't support that flag, so for those
+    Cabal falls back to generating the source with `HsColour`_.
 
 .. cfg-field:: haddock-hscolour-css: PATH
                --haddock-hscolour-css=PATH
     :synopsis: Location of CSS file for HsColour
 
     The CSS file that should be used to style the generated hyperlinked
-    source code (from `HsColour`_).
+    source code (from `HsColour`_). Only used for the HsColour fallback
+    with Haddock versions older than 2.17.
 
 .. cfg-field:: haddock-contents-location: URL
                --haddock-contents-location=URL
diff --git a/doc/references.inc b/doc/references.inc
index 2d586719615..580985c1095 100644
--- a/doc/references.inc
+++ b/doc/references.inc
@@ -17,7 +17,7 @@
 
 .. _Hoogle: http://www.haskell.org/hoogle/
 
-.. _HsColour: http://www.cs.york.ac.uk/fp/darcs/hscolour/
+.. _HsColour: https://hackage.haskell.org/package/hscolour
 
 .. _cpphs: http://projects.haskell.org/cpphs/