Time line for any patch or version upgrade is not specified.
Since, it is not depends on the products you are managing.
It depends on the DB size and hardware specifications, the upgrade will go for hours or days as well.
Example: As per my experience, if you have EPO DB size less or equal to 10GB, and followed all minimum requirements and followed EPO checklist ( KB71825) and took backup.
Disabled, windows update and anti virus and no issues with connecting database.
In this situation, it may take an average of 2 to 4 hours, ( I have seen this situation it completed in 1 hours and some customers it took more than 10 hours)
Hope this answered your query