According to this Ethereum official announcement, the Ropsten will be closed in Q4 2022. The following is the light quote.
Ropsten: Q4 2022
The Ropsten testnet, which ran through The Merge on June 8, 2022, will be shut down in Q4 2022.
Developers who currently use Ropsten as a staging/testing environment should migrate to Goerli or Sepolia.
Now, I can see from the code that Blockcerts seems to support only the Ropsten in Ethereum testnets.
; cert-issuer/conf_ethtest.ini chain = <ethereum_ropsten|ethereum_mainnet>
If so, I think it is time to start thinking about supporting the recommended testnets like Goerli or Sepolia.