there is already another topic in this board about this possibility and there are answers there:
https://bitcointalk.org/index.php?topic=1825035.0also this is what the developer said:
With the current version, the only way is to choose a server that you trust to be on the side of the fork you want. (disable auto-connect)
Right after the hard fork, we will be able to make a new release, that includes a checkpoint, because the block headers will differ.