The state of patents for AAC?

[UKPI]

A few weeks ago, I read an article about Fedora including some parts of the Fraunhofer FDK codec back in 2017. Since only the Low Complexity profile is old enough to clear those requirements, I assumed that only the AAC-LC part of the FDK codec became part of Fedora. There is some information about expired patents for MPEG-2 Video and MPEG-4 Visual (NOT AVC), but details related to patents for AAC are hard to find.

1. Does the inclusion of AAC-LC into Fedora mean that AAC-LC is patent free? (I know that there are patent-free codecs that achieves transparency at lower bitrates. I just want to know this. )
2. Does anybody know or can point to the state of patents related to MPEG-4 AAC profiles (AAC-LC, HE-AAC, HE-AAC v2, etc.)?

Thanks in advance for your answers.

 

[UKPI]

Some updates on the search for status of AAC-related patents. I found a copy of AAC patent licensing agreement. Patents related to AAC-LC, HE-AAC, HE-AAC v2, AAC-LD, AAC-LD v2, Error resilient AAC Scalable, Error resilient AAC-ELD, and xHE-AAC are listed in appendix A.
https://www.sec.gov/Archives/edgar/...1390020023370/ea125930ex10-9_siyatamobile.htm

 

[UKPI]

Here is the list of patents included in that agreement. All the estimated expiration dates are from the search results of Google Patents.