As we have started deprecating some properties introduced earlier (for example: release tag), it might be necessary to introduce two validation modes:

• legacy
• strict

Legacy mode

The mode validates all features ever introduced to package spec, so that we can include also deprecated and old packages. We may need it for publishing logic to resign and revalidate all package revisions.

Strict mode

The strict mode focuses only on current features and guards that developers don't use deprecated features accidentally.

Checklist:

• Make a dry run on the entire package registry to see how many packages will be marked as invalid
• Enforce the use of formatVersion
• Define a mechanism to freeze package spec version
• Discuss about: How to implement different levels of validation?