Kinto

-------------------

**Bug fixes**

- Fix broken Kinto admin (2646)

**Internal Changes**

- Upgrade kinto-admin to v1.27.3

-------------------

**New feature**

- Add ability to disable explicit permissions at object level (ref 893). Use ``kinto.explicit_permissions = false`` to only rely on inherited permissions (see settings docs)

**Internal Changes**

- Distinguish readonly errors in storage backend (``kinto.core.storage.exceptions.ReadonlyError``)
- Upgrade kinto-admin to v1.27.0
- Add support to Python 3.9

-------------------

**Bug fixes**

- Do not break storage implementations (ie. kinto-redis) that rely on ``json`` class attribute (removed in v14.0.0)
- Do not return 400 for ``?_since=null`` (fixes 2595)

-------------------

**Breaking changes**

- Drop the ``strict_json`` option, and use ``ultrajson`` everywhere

**Bug fixes**

- Return 400 if ``_since`` is not ``int`` or ``str`` (fixes 2495)

**Internal Changes**

- Upgrade kinto-admin to v1.26.2

-------------------

**Bug fixes**

- Fix messages duplication in logs (2513)
- Fix resource timestamp unicity (fixes 2472, 602)

**Documentation**

- Refer to proper terms in glossary (2486)

-------------------

**Bug fixes**

- Simplify get_objects_permissions query (2475)