Other server wallets than bitcoind recommended for a ubuntu server I currently run bitcoind on my server that is hosting an online browser game where bitcoin is integrated. The problem I have right now is that we are running out of diskspace with the increasing size of the blockchain and upgrading hardware is not an option at this point.

Is there a server wallet that is not downloading the entire blockchain like bitcond does? If so which ones?
Our current integration is through PHP so it would be good if there is support for that.
The easiest solution would be to upgrade to the recently released version 0.12.0 which allows running a wallet while in pruning mode (which was not possible with 0.11.2). That way you can limit the required diskspace, still have a fully validating node, and don't need to do update your integration.

After the upgrade to 0.12.0 you just start bitcoind with -prune=&lt;n&gt; where &lt;n&gt; gives the amount of MiB of blockchain data you want to store. Be sure to leave some more diskspace for other data, the other files in the bitcoin directory don't count toward the limit.