We'll never disable or cripple features in an effort to force upgrades. You pay one time for your license (it's not a subscription) and that license is good, for that version of the software, for as long as you'd like to use it.
We do release big upgrades to our software now and again and hope you'll find the new features compelling enough to upgrade. But that's up to you! A big upgrade would be moving from YNAB 3 to YNAB 4, or 4 to 5. Those always cost something. If you do choose to upgrade, please take advantage of our upgraders' discount.
Minor updates are always free. An update goes from from YNAB 3.5 to YNAB 3.6 or YNAB 4.8 to YNAB 4.9. Those include bug fixes, stability improvements, and sometimes new features we were too excited to hold until a major release.
If we release a major upgrade and you purchased within the last six months, you get that major upgrade for free. We call that our, "My-timing-couldn't-have-been-worse-I-just-purchased-this-yesterday" guarantee.
Also, our desktop software and the mobile apps work worldwide. You can choose the currency format and set the date/time format when you create a new budget.