Voucher creation on 2.7.1 not working when using current RSA keys

[MFKroon]

Hi,

After migrating from 2.7.0 to 2.7.2 the use and creation of vouchers in the captive portal stopped working.
New voucher rolls show "Failed to sign".
I guess this has to do with the upgrade of OpenSSL to 3.0 and my weak RSA keys (29bit if I recall properly, created it 10 years ago)
The reason I use such a weak key is to reduce the number of digits in the voucher codes: on 2.7.0 these are 6 characters long, where as I regenerate my RSA keys on 2.7.1 the vouchers are 12 long.
In our environment these long voucher codes are not workable.

Is there a way to generate short voucher codes on 2.7.2 through a system patch or something else?

Regards
Michel