Recently, I found that, the calendar item (agenda) created in MIUI 7 Calendar does not sync to my Google Calendar. Then I ignore it.

And until today, I found that, the agenda from Google Calendar does not sync to MIUI7 Calendar too. Then this will be serious. So, I search around the forum, and finally get this solution.

Install Google Calendar! This will solve the calendar syncing problem. Enjoy!

Today I just upgraded the MIUI to version 7. Actually, it prompted for the  upgrade since some times last week. But I failed to upgrade, expected to be server problem.

So, today I determined to find the solution for manual upgrade. The upgrade version is MIUI 7.0.5.0. I visited the official site and searched the ROM, but the official site does not have this ROM. As a result, just did a search, and found the target ROM in the MIUI official forum. Then everything becomes easy now.