What is .wav (obsolete)?

I’m working with some 24/96 files of music I’m making recorded line in using a 2018 model field recorder.
When I have transferred to my hard drive from the recorder they play fine on various players except I noticed a few programmes say they’re 24/96 .wav (obsolete).
I’ve noticed when I amplified the files in Audacity and exported as 24 bit signed PCM some programmes still say .wav (obsolete).
I’m just wondering what are ‘Obsolete’ .wav files?, and considering that I’m planning on sharing these files with friends do I need to convert to “normal” .wav to avoid playing issues?, if so how do I change the set of obsolete .wavs to normal .wav’s ?

“24-bit WAV” is not obsolete. They are widely used in professional studios.
24-bit WAV is less widely supported than 16-bit WAV, and you may well find that some “consumer grade” applications don’t support 24-bit WAV.

To export as 16-bit WAV, select the “Export as WAV” option (https://manual.audacityteam.org/man/file_menu_export.html) and ensure that
“WAV (Microsoft) signed 16-bit PCM” is selected in the export dialog.

The sample rate is set by the “Project Rate” setting in the lower left corner of the main Audacity window. See: https://manual.audacityteam.org/man/selection_toolbar.html#rate

I kikda’ remembered seeing that before and I found this on another forum from 2008:

Re: (Obsolete) WAV format issue.
Microsoft change the RIFF Wave specification to add the WAVE_FORMAT_EXTENSIBLE format tag. All PCM formats with greater than 16 bit quality are now covered by that tag. Any files using the old WAVE_FORMAT_PCM format tag for high quality are considered obsolete.

That’s interesting DVDdoug. It appears that Microsoft have done a turnaround.
Windows XP didn’t support 24-bit WAV with “WAVE_FORMAT_EXTENSIBLE”. Without 3rd party add-ons it only supported 24-bit WAV with the older “WAVE_FORMAT_PCM” standard.
Current versions of Windows Media Player on Windows 10 appear to support both versions, even though Microsoft now say that “WAVE_FORMAT_PCM” is obsolete.