With the release of Nicehash Miner v18.104.22.168, you will be prompted with an upgrade message when you open any previous version of Nicehash Miner. We are however, advising GPU miners to hold off from upgrading at this time.
We have two test rigs for GPU mining, a 3x HD7990 cards (6 gpu's), and a lone R9 280x. Both rigs suffered significant hashrate loss compared to Nicehash Miner v22.214.171.124.
The 3x HD79990 rig on Nicehash Miner v126.96.36.199 was mining Equihash at an average of 1430 Sols/s with minimal hashrate loss on the pool side. After upgrading to v188.8.131.52, the same rig showed an increased hashrate of 1650 Sols/s on the miner, but the hashrate on the pool side tanked to 1100 Sols/s.
The single R9 280x was a little different. On Nicehash Miner v184.108.40.206 it was running a consistent 240 Sols/s on Equishash on the miner side, with minimal loss at the pool. After the upgrade however, this rig had a decreased hashrate on the miner of 100 Sols/s which was consistent with the pool hashrate.
We haven't tested other algorithms, as Equihash is still the most profitable, it gets the focus of our tests.