Rainforest v2 (RFv2) network upgrade is scheduled at height 915000.
Please, update your nodes with following release.
Original Rainforest also contains critical bug which is explained here.
Algo misses exactly one round when running on 80-byte (size of block header) inputs so the last word only passes through the CRC. And it turns out that this last word is the nonce, which open wide window for algo optimizations/cracking (cheers @andrucrypt 😃).
RFv2 intended to fix this vulnerability.
0.16.6 is discarded since it contains not patched version of RFv2 with floating point issues discovered by @djm34 and described here. Since floationg point math is complex and not reliable enough, this bug may caused different outputs on different CPU architectures. Afther discussion with RFv2 devs it was decided to replace floationg point math with integer one to make algo more reliable. Upgrade height has been shifted for 5000 blocks (910000 -> 915000).
Big thanks for everyone who was involved into RFv2 discussion and development!