[TYPO3-core] The "correct" way to upgrade?

[Alexander Stehlik]

> The first step should be the Upgrade Wizard. Each update should ensure
> the required fields are present in the DB.

Yes, I think thats the best way.

It is already done in 
/typo3/sysext/install/Classes/Updates/ExtensionManagerTables.php for 
example and can be done this way for other updates that require new 
database fields.

Another idea that makes it even simpler: create an update wizard step 
that is executed FIRST that CREATES all required fields (no deletion!) 
according to the current table definitions. Than you can be sure that 
you are good to go to run all other update wizard steps that require new 
database fields.

Cheers,
Alex