Major Changes Between v3.x and v4.x:
   Qt Toolkit. Rivendell v4.x uses and is fully compatibile with major
   version 5 of Qt (Qt5). See the INSTALL documents for specifics.
   Display Requirements. A graphical display capable of at least 1400x900
   pixels resolution is required (1920x1080 or higher recommended).
   Date/Time Customizability. Date/Time presentation formats can now be
   customized on the basis of site preferences.
   MySQL Compatibility. Rivendell v4.x aims for full compatibility with
   MySQL 8.0 and earlier versions in their default installation
   configurations.
   RDAirPlay. The rdairplay(1) module has been completely overhauled, and
   now supports dynamic resizeability as well as a revamped level metering
   system.
   RDPanel. The rdpanel(1) module now supports dynamic resizing.
   RDLogManager. It is now possible to disable grid processing on a
   service-by-service basis, thus permitting a complete schedule to
   be generated by an external music scheduler. See the 'Bypassing Grid
   Processing' section in the 'Generating Logs and Reports with
   RDLogManager' section of the Operation Guide for details.
   Many bug and regression fixes. See the 'ChangeLog' for details.
Database Update:
   This version of Rivendell uses database schema version 369, and will
   automatically upgrade any earlier versions. To see the current schema
   version prior to upgrade, see RDAdmin->SystemInfo.
   Be sure to run 'rddbmgr --modify' (as root) immediately after upgrading
   to allow any necessary changes to the database schema to be applied.
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