Noting that your emonCMS on your emonPi is now using the LPL radio format, you also need to update the emonTxs to use the LPL radio format too.
It’s also possible that the RPi is expecting the RFM69 to have the new SPI interface, whereas you’ll be using the old RFM12Pi (albeit with a RFM69CW module) with the serial interface.
My problem is all these changes were done while I was fully occupied with emonLibDB, and I haven’t caught up with all the changes yet.
Seeing @rupert has posted while I was typing, you can keep emonLibCM on the emonPi if you use my RFM69nTxLib (JeeLib Native format) in both the emonPi and your emonTx’s. It’s all documented in The emonPiCM