We haven’t officially published firmware 2.1.8 yet (still finishing up documentation). The main changes in firmware 2.1.8 are focused on OpenSprinkler 3.0, including the integration of ESP8266 core library 2.4 (with improved WiFi), doubling microcontroller frequency, doubling flash frequency, making more flash memory space available for logging (was 1MB before and now it’s 3MB), increasing maximum number of expanded zones (to 72), increasing the maximum number of programs (to 35). Users who have issues with WiFi connection should consider upgrading. However, if you are ok with the current firmware, there is no need to upgrade. After firmware upgrade, there is always the hassle of importing configurations (well, that itself should be fixed soon, so that upgrading firmware no longer requires erasing everything).