by Visvanath Ratnaweera.
Coming from 4.2 or from 3.11 makes a difference between go or no-go. A straight jump to 4.4 is possible only from 4.1.2 or higher! (see the chart and the official release notes linked in the first column)
OK, the statement could also mean that you were on 4.2 but it still had this renderer.php from 3.11. Which means the upgrade to 4.2 has also been done by copying the 4.2 code over the previous (3.11?) code. Better start with a fresh download of 4.4 code or, even better, by cleaning the present 4.2 by replacing the messed up code with a fresh download.
BTW, do you know that Moodle also releases LTS versions every two years? 4.1 and 4.5 are LTS. See https://moodledev.io/general/releases.