I work with Daml.Finance. When I upload dar to the sandbox I see in the logs:
upload-dar did not succeed: "\"ALLOWED_LANGUAGE_VERSIONS(8,f1afed54): Disallowed language version in package fc7e83c... ...Expected version between 1.14 and 1.14 but got 1.15
If you turn on “dev” versions, you are turning on alpha features. Such alpha features are not supported in production (they are alpha). They might also contain changes to the database schema which will not be compatible with the final version. So you will never be able to upgrade your node, as the schema will be in an unexpected state from the perspective of a stable release. The name is chosen such that you really only use it for experimenting around and not for production.