HTC has missed the 90-day deadline it set for itself to get all recent devices updated to Lollipop, but it's not giving up. The Verizon version of the One M8 is getting Android 5.0 today, and you probably know what that means by now.
Lollipop brings new animations, notifications on the lock screen, settings changes, and a card-based app switcher UI. You can check Verizon's update document for an overview of the changes. This OTA will also add band 4 LTE roaming and some enhancements to 3-way calling.
The update should roll out to everyone in the coming days, but you might be able to visit the system menu to trigger it manually.