User: I just updated to the latest version of the AI1EC (2.5.10). After refreshing my calendar page, I found that a lot of events were missing - each iCal feed I have has only 50 events left. I tried manually refreshing my feeds, but still, only 50 events are imported for each feed (and each of the feeds has 400+ events).
The problem was related to the upgrade to WordPress 4.6. This new version changed a little bit the way the HTTP connections are being made to our API.
We released a fix on our API, no need to update the plugin.