Sorry for the delay but i released v2.5.1. This update will disconnect the older nodes and there will be a change to the PoS diff retageting after block 1345000. Please remove the addnodes in the conf file if there are any and delete the peers.dat. If you have issues connecting try these addnodes:
If you shutdown the old wallet before block 1344639 you should be good and just sync up but after you need to remove the chain and redownload or use a backup/snapshot.
I recently compiled the latest releases (tried tar.gz of v2.5 and directly cloning from git repo) on my Odroid U2 using Linaro Ubuntu (Berkeley DB 5.3.15, December 19, 2011). The first time I start the Netcoin daemon, everything is fine. But when I restart the Netcoin daemon using "./netcoind stop" (checking that it was stopped successfully using Linux CMD "ps") followed by "./netcoind", the Netcoin daemon is always crashing with the following exception:
************************
EXCEPTION: St13runtime_error
init_blockindex(): error opening database environment IO error: lock /home/odroid/.netcoin/txleveldb/LOCK: already held by process
netcoin in msghand
terminate called after throwing an instance of 'std::runtime_error'
what(): init_blockindex(): error opening database environment IO error: lock /home/odroid/.netcoin/txleveldb/LOCK: already held by process
When I delete the entire content of the netcoin directory in "/home/odroid/.netcoin" and start the Netcoin daemon, everything works fine and the chain is synchronizing. Whenever I need to restart the Netcoin daemon, I'm getting the error described above, I need to delete the entire directory content in "/home/odroid/.netcoin" and I need to download the entire blockchain again.
Other coins are working like a charm on my Odroid but not Netcoin, so I think it's a problem with Netcoin

Did the older Netcoin versions had this issue aswell or did it start after a certain update? Also see you are using Berkeley DB 5.3 Netcoin uses BDB 4.8