AKA: Open Core
A usefull open-source core is free for all but a premium version with additional functionality, performance, security, or portability is available for money. Enables one-time or recurring payments for the additional features.
Requires:
Variants & Options:
| Characteristics | Value | Note | 
|---|---|---|
| Effort to set-up | Weeks | Creation of a legal entity with licences, documents, etc. | 
| Effort to maintain | Medium | Finding new customers will become necessary | 
| Cost to set-up | Medium | Will require a lawyer to setup the license and contracts | 
| Cost to maintain | Low | Will cause costs for legal or tax related stuff (but should be covered by income) | 
| One-time Income | Medium | Very few companies might pay large amounts if the premium feature is essential | 
| Recurring Income | High | Recurring payments per month or per update | 
| Income Predictability | High | Companies probably want premium version for several years | 
| Full income Threshold | 10+ | |
| Recipient | C | |
| Additional Work | High | Extra work to develop and maintain premium features | 
| Visibility | Low | Easy to forget, ignore, or overlook by users | 
| Necessity to pay | Medium | Might be attractive for companies (e.g., pay for higher security) | 
| Entry Threshold | Medium | Individual contracts for every premium version might be necessary | 
| Countervalue | SW | Customer buys additional features | 
| Scalability | Medium | Scales with the number of commercial users (who need the premium features) | 
| Effort for marketing | Medium | The users might run in situations that require the premium features | 
| Competitors | None | Premium feature would have a proprietary license | 
| Software types | Special | Best for libraries or programs companies build tools upon | 
NOTE: External contributors / companies might develop similar premium features and become competition.