https://github.com/litecoin-project/bitcoinomg/commits/0.8.7-OMG12tag v0.8.7-OMG12 is similar to Luke-Jr's 0.8.7rc1 with the following differences.
* Removed the three OP_RETURN pruning patches. It seemed to have made it incompatible with indexes from 0.8.x.
* Reduced the relay fee by 10x to match the behavior of Bitcoin 0.9.0.
* Added the getnormalizedtxid RPC that was not accepted in Bitcoin Core. This is an experiment.
* Many 0.9 features backported and carried forward from earlier versions of Bitcoin OMG.
You really should be using Bitcoin 0.9. But if for some reason you can't, this version should be fully compatible with data from Bitcoin 0.8.x while including the important bug and security fixes from 0.9. Most of the credit for this round of patches goes to Luke-Jr.
Status Update March 26th, 2014:
v0.8.7-OMG12 contains all of the security and bug fix workarounds pertaining to transaction malleability that were included in Bitcoin 0.9. You really should be using Bitcoin 0.9. Use this only if you need 0.8.x for some reason and you understand how to make backups. At the moment this branch is only lightly tested, so please report back if you run into any issues.