I have a properly indexed site by Google with a few hundred pages, most of the pages re-crawled on a daily basis (according the crawl stats offered by Google Webmaster Tools). Last week, I have added
hreflang tags to all pages by link inclusion within
<head/> section of every page. Yet, within the International Targeting tab of the GWT, I still get a message indicating
Your site has no hreflang tags.
Does anyone know how much time it takes for Google to notice new
hreflang tags on an old well indexed website?