Best Practice / workflow for maintaining a report over time

Hi

I'm trying out Power BI for my team and I'm still a relative beginner.  

I've developed a few reports in the desktop designer app and published them to a workgroup.

I over time a number of others and myself will need to make updates to the report beyond the basics of changing filters etc and will want to use the designer.

I  if we just pass the pbix files around it will be tricky to keep track of the latest version. 

The PBIX file is binary so source control isn't going to work well.

I noticed there is a "download pbix" option in the power bi website but that only seems to be available to to person who initially uploaded the reports. 

So whats the best practice for maintaining reports when you have a team of designers?