diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,3 +1,9 @@
+## 2.6
+
+Compatibility for backend-specific upsert functionality.
+A lucky contributor could add upsert to the MySQL backend now, i.e.:
+INSERT ... ON DUPICATE ...
+
 ## 2.5
 
 * changes for read/write typeclass split
diff --git a/Database/Persist/MySQL.hs b/Database/Persist/MySQL.hs
--- a/Database/Persist/MySQL.hs
+++ b/Database/Persist/MySQL.hs
@@ -111,6 +111,7 @@
         , connStmtMap    = smap
         , connInsertSql  = insertSql'
         , connInsertManySql = Nothing
+        , connUpsertSql = Nothing
         , connClose      = MySQL.close conn
         , connMigrateSql = migrate' ci
         , connBegin      = const $ MySQL.execute_ conn "start transaction" >> return ()
diff --git a/persistent-mysql.cabal b/persistent-mysql.cabal
--- a/persistent-mysql.cabal
+++ b/persistent-mysql.cabal
@@ -1,5 +1,5 @@
 name:            persistent-mysql
-version:         2.5
+version:         2.6
 license:         MIT
 license-file:    LICENSE
 author:          Felipe Lessa <felipe.lessa@gmail.com>, Michael Snoyman
@@ -32,7 +32,7 @@
                    , mysql-simple          >= 0.2.2.3  && < 0.3
                    , mysql                 >= 0.1.1.3  && < 0.2
                    , blaze-builder
-                   , persistent            >= 2.5      && < 3
+                   , persistent            >= 2.6      && < 3
                    , containers            >= 0.2
                    , bytestring            >= 0.9
                    , text                  >= 0.11.0.6