My understanding (based on http://www.hackerfactor.com/blog/index.php?/archives/833-HEI... ) is that HEIC is not built on patents while HEVC is, so HEVC is problematic to use, but HEIC isn’t.
> The HEIC holds the HEIF data that is compressed using HEVC by MPEG
Wrapping a HEVC file in a container does not automatically void any patents of the contained file. Otherwise, anyone can shove any patent encumbered file format in a ".zip" container (or any container/wrapper) and avoid any patent or licensing issues.