Stuck in limbo with pre-RDTS knots and electrs in start9 0.4

Hi,
It appears that there are no bitcoin knots pre-rdts versions that will work with electrs in start9 0.4. Is that correct? Does anyone know if there are plans to get these compatible?

Below seem to be the bitcoin knots version ranges that electrs shows it needs. Neither my knots legacy (29.3.1) nor the pre-rdts version in the community registry (29.3:27) seem to fall within the workable ranges:
Bracket 1: (28.4.0:17 - 29.0.0:0)
Bracket 2: (29.4.0:4 - 30.0.0:0)
Bracket 3: (30.3.0:4 - 31.0.0:0)
Bracket 4: >31.1.0:4

Bitcoin Knots is no longer maintaining their software for the majority-chain bitcoin. Unless someone decides to do so, or forks it (better).