As Daniel pointed out, can you please share with us what are the exact issues you're experiencing after the upgrade, so we can give you a hand in resolving them.
Can you please confirm if you have followed the official upgrade instructions
and also if any of the problemas have not beena ddressed by our recent webinar on the topic: Common Issues with Sitefinity Upgrades
the Telerik team
Do you want to have your say in the Sitefinity development roadmap? Do you want to know when a feature you requested is added or when a bug fixed? Explore the Telerik Public Issue Tracking
system and vote to affect the priority of the items