I’ve just received an email from UptimeRobot:
[IMPORTANT]: The API version you are using is deprecated
We’ve noticed you’re still using our deprecated APIv1 while APIv2 is already available. APIv1 is no longer supported, meaning bugs won’t be fixed and no new features will be added.
We recommend switching to the newer version, you can find the updated Documentation for APIv2 here: https://uptimerobot.com/api/
Let us know if you have questions or need any assistance.
I can only think of a link with MainWP, so can you please check if MainWP is already using the APIv2 version? If not are you planning to change that soon?