How to update identifier_exists through Shopify ?

[user072319]

Hello there,

We've activated Google Shopping shopify app for our store a month ago. In Google Merchant Center > Products  > Diagnostics , we're getting warning like Limited performance due to missing identifiers [gtin, mpn, brand]

To fix this error, how to update identifier_exists for the products which gives this warning?  How to bulky update the products identifier_exists as we've to update 5000+ products? (If we've to do it via excel upload, what is the column name and value we've to provide?)

Any help would be appreciated.