licence fee revenue question

Was doing a bit of research on this company and it meets a lot of my investment criteria. My main 'likes' in bullet point form being:
- High ROE
- No Debt (and good cash balance)
- healthy operating and net margins
- Good earnings stability
- high quality and diversified customer base
- ability to translate earnings into distributable cash
- Low capex. Granted in the last couple of years its increased but the amortisation basically equals capex.
- and finally it trades on a fairly undemanding valuation by my calcs based on modest growth forecasts.

I do still have a query around license fees which I'm hoping someone on here will be able to answer.

Are the license fees a one-off cost to clients when they sign-up to use the software and therefore any future earnings are dependent on the sales team continuing to makes new sales? or;

Are the license fees for a fixed period (eg 5 years) in which case this is actually a recurring revenue and therefore a more predictable revenue stream?

Licencing fees have been quite consistent in achieving good growth year on year for the last 5 years, so I'm inclined to think it's a recurring revenue stream.

With licencing fees making up over half of total revenues even a small percentage movement will materially impact earnings, so this query will be a deciding factor in my decision to invest.