Twiddlebit software was originally provided as shareware and required payment and a registration code to be entered into the software to enable full use. As of November 2017 all software is now freeware.
If you are using a shareware version and need a registration code, feel free to use the following to enable full functionality:
| Product | Username | Code |
| Plan for Windows | freeware | 05909 |
| Plan for Psion | freeware | uBErKLrR |
| Plan5 for Psion | freeware | cUReTDdE |
| Pocket Plan | freeware | 45077 |
| Plan for Nokia | freeware | m3pfafybbpf |
| Plan for UIQ | freeware | 32277 |