diff --git a/hledger-lib.cabal b/hledger-lib.cabal
--- a/hledger-lib.cabal
+++ b/hledger-lib.cabal
@@ -1,5 +1,5 @@
 name:           hledger-lib
-version: 0.12
+version: 0.12.1
 category:       Finance
 synopsis:       Core types and utilities for working with hledger (or c++ ledger) data.
 description:
@@ -58,7 +58,7 @@
                  ,safe >= 0.2
                  ,split == 0.1.*
                  ,time
-                 ,utf8-string >= 0.3
+                 ,utf8-string >= 0.3.5 && < 0.4
                  ,HUnit
 
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