Ways to retain old App version
Yes, but only if you prepare for the downgrade before updating or catch it quickly after updating.


Before upgrading, find the app in question in iTunes.
Right/Control/2-finger click on the app.
Select "Reveal in Finder"
Copy and archive the .ipa file to another location.


Now you have a copy of the current version.

To downgrade...


Find the app you want to downgrade in iTunes.
Right/Control/2-finger click on the app.
Choose "Reveal in Finder"
Delete the .ipa file.
Navigate to your archived copy of the old (previous version) .ipa file in the Finder.
Drag the old .ipa file into iTunes.
The old App version is now in iTunes and ready to sync to devices.


Notes:


Be sure to delete the newer version of the app from your iOS devices before syncing, otherwise the new version will overwrite the old in your iTunes library during the sync process.
You can catch the old version immediately after updating.  Look in your Trash.  Old versions of updated apps are moved to the trash.  Of course, you can't have emptied the trash since updating for this to work.
Be sure automatic downloads are turned off (iTunes preferences, Store tab on a computer; Settings app, Store option on an iOS device).