Suggested stable version of EOS for production?

Hi, guys.
We currently use EOS 4.4.23 for production and are planning to upgrade to 4.6.8. While we tested EOS 4.6.8 with QuarkDB, the performance of which is kind of low. We also tested EOS 4.7.8, but no big improvement. So is there any newer version stable enough for production? Or any suggestions?