It seems that current situation for Team Calendars, if you're running (as we do) latest versions of JIRA and Confluence, is a bit messy.
Some help or guidance will be appreciated:
So, Atlassian, how could we get support for our issue? iCalendar plugin will be updated? Team Calendars itself? Have we need to go back to JIRA 7.0.*? Update anything else? Stop using Team Calendars?
Please, help. Thanks.
Yes, It was in fact part of our fault. But, nevertheless, iCalendar still says it's incompatible with JIRA 7.2.*. Atlassian official answer (through support) is this fact is an error, and add-on is compatible.
By the way, product is still alive. Some days after my question, a new update was released