The View Legal constitution allows the directors to issue shares with any rights they think fit (not just the classes specifically listed in the constitution).
If a new class of shares is to be allotted, the directors would need to pass a resolution specifying what rights attach to those shares and would ideally obtain legal advice regarding the resolution, including in relation to any potential revenue consequences.
Alternatively, the constitution could be updated to incorporate the new class of shares, prior to the allotment.