diff --git a/CHANGELOG b/CHANGELOG
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,5 +1,8 @@
 # CHANGELOG
 
+- 0.12.7.1 (2020-05-03)
+    * Bump `base64-bytestring` dependency upper bound to 1.2
+
 - 0.12.7.0 (2019-12-31)
     * Bump `base` lower bound to 4.8, this drops support for GHC 7.6 and 7.8
     * Add a new `runServerWithOptions` that can be extended in a more
diff --git a/websockets.cabal b/websockets.cabal
--- a/websockets.cabal
+++ b/websockets.cabal
@@ -1,5 +1,5 @@
 Name:    websockets
-Version: 0.12.7.0
+Version: 0.12.7.1
 
 Synopsis:
   A sensible and clean way to write WebSocket-capable servers in Haskell.
@@ -82,7 +82,7 @@
     async             >= 2.2    && < 2.3,
     attoparsec        >= 0.10   && < 0.14,
     base              >= 4.8    && < 5,
-    base64-bytestring >= 0.1    && < 1.1,
+    base64-bytestring >= 0.1    && < 1.2,
     binary            >= 0.8.1  && < 0.11,
     bytestring        >= 0.9    && < 0.11,
     bytestring-builder             < 0.11,
@@ -141,7 +141,7 @@
     async             >= 2.2    && < 2.3,
     attoparsec        >= 0.10   && < 0.14,
     base              >= 4      && < 5,
-    base64-bytestring >= 0.1    && < 1.1,
+    base64-bytestring >= 0.1    && < 1.2,
     binary            >= 0.8.1  && < 0.11,
     bytestring        >= 0.9    && < 0.11,
     bytestring-builder             < 0.11,
@@ -169,7 +169,7 @@
     async             >= 2.2    && < 2.3,
     attoparsec        >= 0.10   && < 0.14,
     base              >= 4      && < 5,
-    base64-bytestring >= 0.1    && < 1.1,
+    base64-bytestring >= 0.1    && < 1.2,
     binary            >= 0.8.1  && < 0.11,
     bytestring        >= 0.9    && < 0.11,
     bytestring-builder             < 0.11,
@@ -199,7 +199,7 @@
     async             >= 2.2    && < 2.3,
     attoparsec        >= 0.10   && < 0.14,
     base              >= 4      && < 5,
-    base64-bytestring >= 0.1    && < 1.1,
+    base64-bytestring >= 0.1    && < 1.2,
     binary            >= 0.8.1  && < 0.11,
     bytestring        >= 0.9    && < 0.11,
     bytestring-builder             < 0.11,
@@ -227,7 +227,7 @@
         async             >= 2.2    && < 2.3,
         attoparsec        >= 0.10   && < 0.14,
         base              >= 4      && < 5,
-        base64-bytestring >= 0.1    && < 1.1,
+        base64-bytestring >= 0.1    && < 1.2,
         binary            >= 0.8.1  && < 0.11,
         bytestring        >= 0.9    && < 0.11,
         bytestring-builder             < 0.11,