I don't heard yet that it didn't work but if it didn't work you can able to use coinb.in to generate an unsigned transaction and sign it with your old Electrum wallet.
The serialization of the raw transaction generated by Coinb.in isn't compatible with Electrum for quite sometime. The compatibility issue would likely remain as Electrum decided not to fix it in favour of PSBT and coinb.in doesn't support coinb.in and hasn't changed their raw TX serialization.