Downgrading specific packages with apt

[solitone <solitone@mail.com>]

I am on Debian 9 (scratch), and I have a MacBook Pro 12,1 with retina display.

Few days ago I upgraded Google Chrome from version 58 to 59:
google-chrome-stable:amd64 (58.0.3029.110-1, 59.0.3071.86-1)
This new version no longer supports HiDPI. As a result everything in Chrome is 
so small that I would need a magnifying glass!

Not a great issue though, since I usually work with Chromium, not Chrome. But 
today apt has proposed the very same upgrade for Chromium too:

chromium/testing 59.0.3071.86-1 amd64 [upgradable from: 58.0.3029.96-1]
chromium-driver/testing 59.0.3071.86-1 amd64 [upgradable from: 58.0.3029.96-1]
chromium-l10n/testing 59.0.3071.86-1 all [upgradable from: 58.0.3029.96-1]
chromium-shell/testing 59.0.3071.86-1 amd64 [upgradable from: 58.0.3029.96-1]

I suspect if I upgrade I would end up having the same HiDPI issue with 
Chromium. So for the time being I have put on hold those four packages. But 
I'd like to test whether this is true. What should I do to be able to 
downgrade to version 58.0.3029.96-1 in case 59.0.3071.86-1 does in fact break 
HiDPI? I always have some difficulties when I need to downgrade with apt. This 
time I want to be prepared.

Thanks!