Will someone with a Belgian banking app still be able to scan a QR code created with the Payconiq by Bancontact app?

Yes. You can still create QR codes in the same way as before with your Payconiq by Bancontact app, and these codes can be scanned via Payconiq by Bancontact or with one of the bank apps listed below.

The reverse is also true: Payconiq by Bancontact users can still scan QR codes created with the bank apps listed below.