[TYPO3-english] Updating from version 3.7.0 to 4.2.8 anything to be aware of?

[Morten Kjems]

Hi

I have been asked to update a site from version 3.7 to version 4.2.8

I have not updated from that old versions before and I wonder if there 
is anything special to be aware to insure a smooth update?

/Morten