Version 5.15

Changed

• MP4/M4A : Non-standard fields are now all saved even if you don't provide any namespace.
  • If <field name> is 4 characters or shorter, the field will be persisted as a standard atom;
  • If <field name> is longer than 4 characters
    • If you provide just a bare name (e.g. "MY_CUSTOM_FIELD"), it will be persisted as a ---- custom atom, using the com.apple.iTunes namespace
    • If you provide a namespace using the : separator (e.g. "my.namespace:MY_CUSTOM_FIELD" or "----:my.namespace:MY_CUSTOM_FIELD"), it will be persisted as a ---- custom atom, using the namespace you provided
• MP4/M4A : As a consequence of the above change, all non-standard fields persisted with the com.apple.iTunes namespace are now listed with their bare name (i.e. without their namespace) in AdditionalFields
  • Before v5.15 : AdditionalFields key is ----:com.apple.iTunes:MY_CUSTOM_FIELD
  • Starting from v5.15 : AdditionalFields key is MY_CUSTOM_FIELD
• MP4/M4A : The Conductor metadata is now written to the ©con atom instead of ----:com.apple.iTunes:CONDUCTOR. The latter is still properly read and mapped

Fixed

• APEtag : Properly read lyrics with more than 100 characters
• APEtag : The Publisher metadata is now properly mapped to IMetadata.Publisher and won't appear in AdditionalFields anymore
• Track.CopyMetadataTo doesn't ignore embedded images upon saving anymore

Thanks to @Agagamand for his precious help on these ones 👍

Binaries are available from nuGet