2 variables are related to the upgrade of files of previous version to the current.

It is important because when a file has been upgraded to a newer version it can not be modified anymore using the previous.

For example, the objects schema has changed from 2019-R2 to 2020-R1 (no change from 2020-R1 to 2020-R2).

If you open a 2019-R2 file in 2020-R1 (or R2) you want to control if it could be upgraded or not.

Variables are:

• CIVIL_UPGRADE_PROMPT_OFF
• CIVIL_OPEN_OLD_READONLY

1. You want to give the choice to upgrade or not. 
   Don't set any variable (and check that none are set: they must not appear in variables list in File>Settings>Configuration>Variables).
   Note that when file is updated, a copy of the original is created (.BAK).
   
   
2. You DON'T want to give the choice and DON'T want to upgrade files
   Set both CIVIL_UPGRADE_PROMPT_OFF and CIVIL_OPEN_OLD_READONLY whatever the value.
   But to be consistent it should be: CIVIL_UPGRADE_PROMPT_OFF=1 and CIVIL_OPEN_OLD_READONLY = 1
   Files will be opened as readonly with no warning or choice.
   
   
3. You want to automatically update files with no prompt
   Set only CIVIL_UPGRADE_PROMPT_OFF, whatever the value.
   But to be consistent it should be: CIVIL_UPGRADE_PROMPT_OFF=1 (and check that CIVIL_OPEN_OLD_READONLY is undefined)