diff --git a/LICENSE b/LICENSE
--- a/LICENSE
+++ b/LICENSE
@@ -48,7 +48,7 @@
 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-Copyright (c) 2015-2017
+Copyright (c) 2015-2021
         Drexel University.
 
 Redistribution and use in source and binary forms, with or without
diff --git a/Text/PrettyPrint/Mainland.hs b/Text/PrettyPrint/Mainland.hs
--- a/Text/PrettyPrint/Mainland.hs
+++ b/Text/PrettyPrint/Mainland.hs
@@ -337,7 +337,8 @@
 -- | The document @'group' d@ will flatten @d@ to /one/ line if there is
 -- room for it, otherwise the original @d@.
 group :: Doc -> Doc
-group d = flatten d `Alt` d
+group Empty = Empty
+group d     = flatten d `Alt` d
 
 -- | The document @'flatten' d@ will flatten @d@ to /one/ line.
 flatten :: Doc -> Doc
@@ -479,9 +480,10 @@
 -- | The document @'align' d@ renders @d@ with a nesting level set to the current
 -- column.
 align :: Doc -> Doc
-align d = column  $ \k ->
-          nesting $ \i ->
-          nest (k - i) d
+align Empty = Empty
+align d     = column  $ \k ->
+              nesting $ \i ->
+              nest (k - i) d
 
 -- | The document @'hang' i d@ renders @d@ with a nesting level set to the
 -- current column plus @i@, /not including/ the first line.
diff --git a/mainland-pretty.cabal b/mainland-pretty.cabal
--- a/mainland-pretty.cabal
+++ b/mainland-pretty.cabal
@@ -1,11 +1,11 @@
 name:           mainland-pretty
-version:        0.7.0.1
-cabal-version:  >= 1.6
+version:        0.7.1
+cabal-version:  >= 1.10
 license:        BSD3
 license-file:   LICENSE
 copyright:      (c) 2006-2011 Harvard University
                 (c) 2011-2012 Geoffrey Mainland
-                (c) 2015-2019 Drexel University
+                (c) 2015-2021 Drexel University
 author:         Geoffrey Mainland <mainland@drexel.edu>
 maintainer:     Geoffrey Mainland <mainland@drexel.edu>
 stability:      alpha
@@ -20,11 +20,14 @@
                 appropriate #line pragmas and its ability to produce output
                 in the form of lazy text using a builder.
 tested-with:    GHC==7.4.2, GHC==7.6.3, GHC==7.8.3, GHC==7.10.3, GHC==8.0.2,
-                GHC==8.2.2, GHC==8.4.3, GHC==8.6.5, GHC==8.8.1
+                GHC==8.2.2, GHC==8.4.3, GHC==8.6.5, GHC==8.8.4, GHC==8.10.4,
+                GHC==9.0.1
 
 build-type:     Simple
 
 library
+  default-language: Haskell2010
+
   exposed-modules:
     Text.PrettyPrint.Mainland
     Text.PrettyPrint.Mainland.Class
@@ -32,7 +35,7 @@
   build-depends:
     base         >= 4.5  && < 5,
     containers   >= 0.2  && < 0.7,
-    srcloc       >= 0.2  && < 0.6,
+    srcloc       >= 0.2  && < 0.7,
     text         >  0.11 && < 1.3,
     transformers >  0.3  && < 0.6