If you already upgrade your Qlikview to 12.5 SR2, You mightr see the issue with font size in Windows 10.
In fact It's wired that this issue didn't exits in previous version. I think this issue is a kind of fundamental issue that is happening beacuse Qlikview is nor responsive as Qliksense. So every things in QLikview is fixed-size and it dosn't change when windows display setting or resolution change.
Any way to fix the issue I found two way:
Changing Windows display resolution (to 1280X720)
Changing windows font size to 100% and using Qlikview plug in zoom facility to enlarge the dashboard