Querying by last sync time in Realtyna WPL MLS Addon RETS

If you are using the Realtyna MLS Addon for Realtyna WPL for WordPress to download listings using RETS, you might have come across the need to query only new data from the last time a sync / query was run (successfully). The major benefit of course being a smaller and faster download and processing of new MLS data. Rather oddly this functionality, at least as of version 4.2.6 of the MLS Addon, exists but is not documented. From the MLS Query screen, when editing a query you can set special text keywords in the Advanced section of the Query Wizard for the value Date/Time fields. These keywords are automatically expanded in the resulting RETS query with values as shown below.

Start Date – The date of the last successful sync
End Date -[Start Date] + [Sync Interval] days (default sync interval is 1)

KeywordDescriptionExample (Start Date = 2020-01-01, End Date = 2021-02-10)
date+sOn or between [Start Date] and [End Date]Photo_updt=2020-01-01-2021-02-10
date+tzl[End Date] with Time in UTCPhoto_updt=2021-02-10T00:00:00.00Z
[Start Date] with Time in UTCPhoto_updt=2021-01-01T00:00:00.00Z
date+tOn or after [Start Date] with TimePhoto_updt=2021-01-01T00:00:00+
dateTOn or between [Start Date] with Time and [End Date] with TImePhoto_updt=2021-01-01T00:00:00-2021-02-10T00:00:00
date+On or after [Start Date]Photo_updt=2021-01-01+

For further information you can view the source for create_query() in libraries/services/addon_mls.php.