Upgrading CFP3 to CIS35 questions

Confused about migrating a config from CFP3 to CIS35.

To migrate a CFP 3 config to CIS 35, is this still valid?

If it is, why does an automatic upgrade work without the need to do the above?

In other words, if the automatic upgrade correctly imports and used the old configuration,
why can’t a CFP3 exported configuration be imported into a clean CIS35 install
without “polluting” the default configurations?

Is there some part of the automatic upgrade, which correctly imports, that
is missing in a clean install of CIS35?

Hi comoe

If you are upgrading to 3.5 from 3 you should do a fresh install without importing your config. This is because 3.5 has some additional protection that you will not get from an importing config.