Dear all, 

It seems that Heroku has made some changes on November 28th regarding the deletion of free dynos, postgres, etc. (See below as the email information)

"As we previously communicated, starting November 28th, 2022, free Heroku Dynos, free Heroku Postgres, and free Heroku Data for Redis® will no longer be available. You must take action to continue to operate your applications on our service and prevent the deletion of your free databases. "

On November 29th, two sessions in my lab encountered some application errors that severely disrupted the lab experiments. Both impacted sessions have been run multiple times before (so the oTree program and previous Heroku application worked fine). Both impacted sessions happened after one session had been successfully run on Heroku. I wonder whether the changes on Heroku side may require our oTree users to adopt some changes too. Specifically, do we need to reset our database every time we finish running one session? Do we need to change the dyno settings to a higher level? (By the way, both impacted experiments were using study and paid dynos and postgres). 

Any thoughts and suggestions will be much appreciated.