For older devices, iRemove Tools is unnecessary. Use Checkra1n jailbreak followed by a free bypass script like "F3arRa1n" or "iCloudBypassTool." These never throw a "not supported" error on A11 devices.
The software works by exploiting specific hardware vulnerabilities or communication protocols between the device and Apple’s activation servers. Because Apple constantly patches these vulnerabilities, iRemove Tools releases frequent updates.