Tomestone gear and normal/savage raid tiers advance together on even-numbered patched (.0 .2 .4). Alliance raids and "other stuff" advance on odd-numbered patches (.1 .3 .5).

The middle patches (.x5.. occasionally others) are usually to add content that didn't fit nicely into the patch timelines. This is usually where relic progression happens, and in the case of 5.45, is where BLU was advanced a bit. So that sort of thing.

The short version here is that the tomestone gear doesn't advance again until the next expansion. You can expect an alliance raid that awards i520 gear and a currency that drops from it and combined with the other two to buy upgrade tokens for i520 tomestone gear (previously only available in the savage Eden tier). As for the "other stuff" well... we dunno yet. There's always other stuff though. There's a live letter at the beginning of April that will likely explain some of it.