CONJ-895 usage of useBatchMultiSend (another param was also changed). This was merged into 2.7.5. When using this driver we explicitly now set useBatchMultiSend to false.
However, it does not seem to work correctly. Actually, when our app sends multiple inserts into a single table, the communication hangs in the middle and we are left with a connection leak.
Downgrading to 2.7.4 fixes the issue for us.