What you are agreeing to.
OPEN SOURCE
Most common platforms are open source and free to use, modify and host.
The licence may require that modifications you distribute are also open source. Using it for your own site does not trigger that.
COMMERCIAL EXTENSIONS
Premium themes and plugins are usually sold with a licence covering a number of sites and a period of updates.
When the licence lapses, the software continues working and stops receiving updates. That is a security problem, not merely a feature limitation.
WHAT LAPSED LICENCES ACTUALLY MEAN
You are running software that no longer receives security fixes. Automated scanners find vulnerable versions regardless of whether you paid.
Renew, or replace it.
PER-SITE LICENCES
Check what you bought. A single-site licence used on five client sites is a breach, and the developer can revoke it.
NULLED SOFTWARE
Covered elsewhere and worth repeating: it is not a licence question but a security one. The code has been modified by someone whose interests are not yours.
FOR CLIENT WORK
Make clear who buys and renews licences. Unclear arrangements end with lapsed licences nobody owns.
