Change 27687
SDP Legacy Upgrade Guide doc updates:
* Customer feedback incorporated. THANK YOU!
* Added new 'Upgrade systemd service files' section.
* Cleaned up some incomplete text.
* Fixed typo 'MAILLOST' -> 'MAILLIST'.
* Added notes to crontab handling to deal with change from
daily_backup.sh to daily_checkpoint.sh and removal of
recreate_db_*.sh scripts.
* Customer feedback incorporated. THANK YOU!
* Added new 'Upgrade systemd service files' section.
* Cleaned up some incomplete text.
* Fixed typo 'MAILLOST' -> 'MAILLIST'.
* Added notes to crontab handling to deal with change from
daily_backup.sh to daily_checkpoint.sh and removal of
recreate_db_*.sh scripts.