Running "flutter pub get" in project_name...                      
The current Dart SDK version is 2.16.2.

Because no versions of qr_flutter match >4.0.0 and qr_flutter <1.1.2 requires SDK version >=1.8.0 <2.0.0, qr_flutter <1.1.2-∞ or >4.0.0 is forbidden.
And because qr_flutter >=1.1.2 <2.1.0 55 depends on qr ^1.0.0, qr_flutter <2.1.0 55 or >4.0.0 requires qr ^1.0.0.
And because qr_flutter ^2.1.0 55 depends on qr ^1.1.0 and qr_flutter ^3.0.0 depends on qr ^1.2.0, qr_flutter <4.0.0-∞ or >4.0.0 requires qr ^1.0.0.
And because qr_flutter 4.0.0 depends on qr ^2.0.0 and barcode >=2.2.0 depends on qr ^3.0.0, qr_flutter is incompatible with barcode >=2.2.0.
And because printing >=5.7.3 depends on pdf ^3.7.2 which depends on barcode ^2.2.0, qr_flutter is incompatible with printing >=5.7.3.
So, because sflo_zaiko depends on both qr_flutter any and printing ^5.8.0, version solving failed.
pub get failed (1; So, because project_name depends on both qr_flutter any and printing ^5.8.0, version solving failed.)
exit code 1

I did 'flutter upgrade', change version of these dependencies etc.

(changing printing: ^5.8.0 to printing: any worked. But it does cause another error so printing must be version 5.8.0)

I've struggling all day long