Rollup period of office 365

 Hello,

 When is the rollup period for office 365 and where can we find those updated information (any links) ?

Example : This week one rollup done for any issue or for any new feature and how long for the next rollup to take place .

Is there any default time period  for rollup to occur and did we get any email notifications for those rollup ?

Regards,

Rajeshkumar Srinivasan.