diff --git a/libraries/liblmdb/lmdb.h b/libraries/liblmdb/lmdb.h
index 588152778c..9c97fe7739 100644
--- a/libraries/liblmdb/lmdb.h
+++ b/libraries/liblmdb/lmdb.h
@@ -1054,7 +1054,7 @@ int  mdb_env_set_maxdbs(MDB_env *env, MDB_dbi dbs);
 
 	/** @brief Get the maximum size of keys and #MDB_DUPSORT data we can write.
 	 *
-	 * Depends on the compile-time constant #MDB_MAXKEYSIZE. Default 511.
+	 * Depends on the page size. Can only be used after #mdb_env_open().
 	 * See @ref MDB_val.
 	 * @param[in] env An environment handle returned by #mdb_env_create()
 	 * @return The maximum size of a key we can write