The first stable release of the new 1.18 series is now available containing the collective fixes and improvements put into all the previous 1.17 releases by the many people who have contributed to Wesnoth over the last two and a half years! For more details see https://r.wesnoth.org/t57843 as usual, or take a look through https://www.wesnoth.org/start/1.18/

However, if you decide you need to remain on 1.16 for the time being, please see here for instructions on how to downgrade. The instructions are from the previous update from 1.14 to 1.16, but the same steps still apply.