Borrowing the reply from this thread
OpenSSL::Digest::Digest has been discouraged to use from very ancient era such as Ruby 1.8 and finally was deprecated recently.
If you search for the error message, you will see that a lot of gems, including fog, were still using the deprecated syntax.
I assume it will take a while before all the gems will be updated. If you came across the deprecation in one of the libs you use, I encourage you to report it to the maintainer.
Here’s a few examples
- https://github.com/fog/fog/pull/2473
- https://github.com/alexreisner/geocoder/pull/580
- https://github.com/ruby/ruby/pull/446
It’s likely your Rails app depends on a gem that is using that old syntax.