For an existing installation of EPLAN P8 2.1.4, follow these steps to enter your key:

Before discussing licensing, it’s important to understand what this version represents. EPLAN Electric P8 2.1.4 was released around 2010–2012. The “127l” likely refers to a specific patch or build number. This version runs on Windows 7, Windows XP, and early Windows 10 builds. Many manufacturers still use it because migrating projects to newer versions requires time and resources.