New OSX and Time machine question

[beachBOYken]

Hi

When the new mac OS X sierra is released, Im thinking about doing a clean install possibly, due to a few problems on el cap.

I have a connected external hdd used for TM backup.

When I do the clean install and everything is fine should I format the TM backup and start a fresh.

Im just wondering if old TM backups of el cap will be ok still on the hdd or if a new mac OS X requires a clean hdd?

Thanks

 

[flying grouse]

no, you're fine just using the same hdd. that means you can still go back to el cap if there is any problems.

TM backups continually update until there is no more room and will delete the oldest first to make more space.