There's a thread specifically on the current event, it's located here:
https://forums.storm8.com/showthread...rie-Tale-event that is likely to offer you more help.
Since I'm here, my suggestions are:
Hit the green "GO" button after the task that wants you to upgrade the tree. It may not seem like it, but sometimes doing this can get the game to acknowledge things it was ignoring before so it's worth a try.
If the tree still won't show the upgrade option, I'd try all the standard fixes such as resetting/reinstalling the game.
If you're
still unable to upgrade after trying all possible fixes on your end, then your issue seems to be a technical one which means it's time to call in the experts. You'll want to either post in the Bugs & Issues forum located here:
https://forums.storm8.com/forumdispl...ugs-amp-Issues or open a support ticket with s8 here:
https://support.storm8.com/hc/en-us/requests/new.
Just keep in mind that s8 is closed for the weekend and their hours may be altered this week due to the holiday... basically you may not get a reply right away. Good luck!