How do I open and accept calendar invitations? Phone is a Samsung Galaxy S SCH-I500 2.3.4 firmware. US Cellular carrier, I'm using gmail app and email app; neither recognize format. phone's native calendar and google cal online. All else synced and working beautifully. 3rd party software for ical attachments (buy me a beer guy) didn't parse correctly...
You can use Invitation Plugin to open ICS files directly in Google Calendar application. It can open ics invitations from email attachments or from files on sdcard.
It requires at least Android 4.x+ (Ice Cream Sandwich) to run.
Note: I am an author of this app.