With the transition from Eastern Daylight Time (EDT) to Eastern Standard Time (EST) as part of Daylight Savings (DST), the appoinmtents+ plugin is messing up appointments booked before the DST change because the plugin assumes that a day always will be 86400 seconds long, as demonstrated from the following code snippet.
$time = strtotime( $date, $appointments->local_time ) + ($add * 7 * 86400) ;
In most of the Western world, that is an incorrect assumption, twice per year when we transition to/from Daylights Savings Time.
Although it's a (little bit of a) challenge on installs using PHP versions prior to v5.3, a simple way to not have to worry about DST is implementing the DateTime() functionality. It automatically manages DST changes (assuming the code then uses intervals, i.e.
+ 1 week or