It update everything. But sometimes a display template will revert to an old version. On first start I check the pages and see the old javascript code in there. (so i manually edit the html file to fix it).
I dont have this problem with any other elements in modules except sometimes with display templates.
The reason why the display template didn't update costed me a long time...this will save you some hours:
Inside the display template I included a JavaScript .js Inside the same display template I also had a JavaScript function with the same name
I guess it was skipped and an older version was put back in place during activation.
solved