Shared Links broken after upgrade

Hello, I have upgraded our Owncloud as described.

After update all "Share links" are broken. When I try to access
a link I get a password login. I also noticed that the links
have changed


Is it possible to make the old links work again? Can someone advice?

Steps to reproduce
1. upgrade from to

Expected behaviour

Actual behaviour
All user Share links are broken

Server configuration
Operating system: debian 8
Web server: apache 2.4.10
Database: mariadb 10.0.29
PHP version: 5.6.30
ownCloud version (see ownCloud admin page):
Updated from an older ownCloud or fresh install:
Special configuration (external storage, external authentication, reverse proxy, server-side-encryption):

ownCloud log (data/owncloud.log)

Please paste possible errors in the following code block, see for more info

Integrity status for oC9+

No errors have been found.

Can you show us the content of owncloud.log during clicking on the link, please?

That's the next issue I can't fix. The owncloud.log is beeing generated
but it remains empty regardless what level I chose.