查資料的時候翻到「ISC Software Licenses」這頁，發現從 2015 年開始 ISC 就打算換掉原先的 ISC license，陸陸續續都轉移到 MPL 2.0...
在維基百科的頁面上可以看到一些說明，包括 Kea、BIND 與 ISC DHCP 都已經換完了：
In 2015, ISC announced they would release their Kea DHCP Software under the Mozilla Public License 2.0, stating, "There is no longer a good reason for ISC to have its own license, separate from everything else". They also preferred a copyleft license, stating, "If a company uses our software but improves it, we really want those improvements to go back into the master source". Throughout the following years, they re-licensed all ISC-hosted software, including BIND in 2016 and ISC DHCP Server in 2017.
不過 INN 還是維持著 ISC license，應該是因為不算是 ISC 的正式產品？