I'm suddenly seeing database connection errors such as
could not retrieve server_version: tlsv1 alert protocol version or
SSL error: tlsv1 alert protocol version (PG::Error).
Users of Heroku Postgres may start seeing errors when connecting to the database if their client is using a deprecated TLS version. As part of ongoing maintenances performed on Heroku Data Services, existing services are being migrated to new and updated servers that do not accept connections using TLS v1.1 or lower.