Workaround:
Edit the current maintenance plan
Disable Cleanup history step
Add exec T-SQL step with command
exec [LiteSpeedLocal]..[LiteSpeed_DeleteActivity] @delLocal=1,@purgeDeleted=1, @delLogshipping=1, @delStatus=1, @delUnit=3, @delUnitType='DAYS'
In the example above history older than 3 days will be purged. (@delUnit=3)
These arguments can be configured as desired:
@delUnit= Any integer
@delUnitType='[HOURS, DAYS, WEEKS, MONTHS, YEARS]'
