Error: failed moving app: This feature is not available for Postgres apps at this time

Looks like your source App was running an older version… There’s a known issue when migrating from < v0.0.43 to >= v0.0.43 that can lead to collation issues.

It’s annoying, but can be manually addressed by following the instructions here:

Alternatively, you can perform pgdump/pgrestore which is what the fly pg import process does behind the scenes.