Try a chain catcher first.

In my case, I had to put in a better front derailleur due to fit issues in placing the chain catcher. I don't know if it was the better front derailleur or the chain catcher that solved the problem, but I was super happy that my hybrid did not derail any more when going uphill.
____________________________________

2012 Specialized Amira Elite, upgraded carbon handle bars, Jett saddle 143mm switched to 145mm 2012 Selle Italia Max SLR Gel Flow saddle

2011 Specialized Ariel Sport,suspension post,Serfas Rx Women's Microfiber saddle