They have to continue meeting the requirements of their level (in this case L4) but there's no expectation of growth beyond that level.
Even the old system, where there was a formal expectation for every SWE to grow to L5, wasn't uniformly enforced. One person I know joined as an L4 SWE twelve or so years ago; they're still an L4 SWE.
Even the old system, where there was a formal expectation for every SWE to grow to L5, wasn't uniformly enforced. One person I know joined as an L4 SWE twelve or so years ago; they're still an L4 SWE.