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We do not guarantee actual ABI compatibility across minor upgrades, so plugins built for one minor version cannot be assumed to run in later minor versions without being rebuilt.
For IdP V4.0 and later, we do not support any external code which relies on deriving classes which are subclasses of BaseContext. The motivation is that this restriction allows us to add methods to our context classes (which could break external code which implements methods with the same signature).
Storage Formats
Some functionality may rely on persistent or transient storage, whether in the form of database schema, memcache usage, cookies, or HTML Local Storage. In such cases, we may choose to document these formats and denote them as a stable API, or we may not. If not explicitly designated as an API, storage formats should be assumed to be an implementation detail that may change across releases. The specific changes we will make to such formats are outlined further below.
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