Calendar 2.4

No permission to buy ($25.00)
Calendar v2.4 changes:

Fixed issue with Calendar remove single.
Calendar v2.3 changes:

Added function to delete single calendar event dates in Calendar remove overlay.
Calendar v2.2 changes:

Deleted orphaned phrase.
Calendar v2.1 changes:

Fixed issue with navigation arrows on calendar page.
Calendar v2.0 changes:

Added function to add recurring calendar events.
Calendar v1.9 changes:

Improved navigation buttons on calendar page. Calendar tab now highlights when clicked.
Calendar v1.8 changes:

Added prefix support to calendar events widget.
Calendar v1.7 changes:

Fixed problem with holiday's not showing if days were single digits.
Calendar v1.6 changes:

New PHP code and template code. New Calendar add overlay.
A security issue has been identified in earlier versions of this add-on. The issue allows a cross site scripting (XSS) attack to potentially be triggered via a specially crafted username. XSS issues may allow an attacker to steal data (including cookies) or force a user to take actions without their consent or knowledge (possibly including administrative actions).

I strongly recommend all users to upgrade to the latest version of Calendar v1.5 to resolve the issue as soon as possible.