Cannot reinstall Dropbox on iPhone running iOS 6

[dropo]

Had to reset the iPhone and reinstall Dropbox. It's iPhone 4S (iOS 6.1.3), and yes, I know it's old. However, Dropbox was working fine on it. Now App Store gives me "This App Is Incompatible With This iPhone". Well, I have it in my Purchased app list. Surely there must be a way to put the 'last compatible version' back where it was working before. Please, working solution needed. Thanks

[Mark]

If there is a working version available Apple will let you do that via https://smile.helpscoutdocs.com/article/77-i-have-ios-7-how-can-i-download-a-version-of-the-app-whic... , however, if there isnt then I'm afraid there isnt a way of doing so and you'll need to just use the mobile website. 

[dropo]

Mark, thanks for your fast reply! Before, I was able to use this method and it worked. Not now, unfortunately... Do you know if 156 was the last version compatible with iOS 6? I wish I saved my apps locally (even though this wouldn't work as they appear to flip the kill switch on server side for old versions).