This package throws warnings on php 7.4

[russellmann]

Array and string offset access syntax with curly braces is deprecated.
/includes/date.php on line 225, 254, 260
includes/ical.php on line 63, 841

[russellmann]

Thank you for fixing some of them. Created a pull request to fix a couple more that were missed.

[mattbisme]

I'm still seeing this myself on line 260.