Hey here is Stefan from OpenSprinkler Germany.
Some of my customers also have the problem that after some time OpenSprinkler cannot reconnect.
However, instead of trying to reconnect again and again, I take a different approach. If no WiFi connection is established after 120s, WiFi is deactivated for 5min, 10min, 20min and finally 40min, in between connection attempts with 120s connection time.
The firmware is based on the very latest git master version of today. So I am looking for some testers for the firmware.
The firmware is here:
http://opensprinklershop.de/wp-content/uploads/2020/08/OS2196_wifi_sleepmode.bin
Please post test results here in this thread