Google’s John Mueller said on Twitter that while self-referential hreflang is optional, it is also good practice to implement it.
Google updated the help docs where it use to say:
If you have multiple language versions of a URL, each language page should identify different language versions, including itself. For example, if your site provides content in French, English, and Spanish, the Spanish version must include a rel=”alternate” hreflang=”x” link for itself in addition to links to the French and English versions. Similarly, the English and French versions must each include the same references to the French, English, and Spanish versions.
The document was completely revamped and removed that specific language. John has not replied specifically to the doc change but he said:
Self-referential hreflang is optional, but you’re right – it’s a good practice!
— John ☆.o(≧▽≦)o.☆ (@JohnMu) June 29, 2018
In which, he replied:
Hold on, that’s not what it says here … https://t.co/AO5VCbiy1n”If you have multiple language versions of a URL, each language page should identify different language versions, including itself”. I’m confused now. It seems like the self reference has been deprecated?
— Andrea Moro (@andrea_moro) June 30, 2018
I am not sure why John didn’t reply to the last tweet?
Forum discussion at Twitter.