We use paperclip which is not supported anymore in favor of ActiveStorage introduced with Rails 5.2

There are multiple migration guides that promise no downtime that we can draw experience from:

• https://blog.carbonfive.com/safely-migrating-from-paperclip-to-active-storage/
• https://www.elitmus.com/blog/technology/migration-from-paperclip-to-activestorage/
• https://medium.com/sortlist-engineering/migrating-from-paperclip-to-activestorage-a-different-approach-4bffa2260e17
• disable checksumming

Alternatively we can migrate to a maintained fork of paperclip - kt-paperclip. Downside is that it has much smaller and diminishing community but on the other hand it may spare us database migrations for years in case we don't hit bugs or lack of functionality.