remove the RetireBugBackwardsCompatibilityMode

[marten-seemann]

No description provided.

[codecov]

Codecov Report

Merging #3213 (b2857b5) into master (e9d12b7) will decrease coverage by 0.00%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #3213      +/-   ##
==========================================
- Coverage   85.40%   85.40%   -0.00%     
==========================================
  Files         134      134              
  Lines        9825     9822       -3     
==========================================
- Hits         8391     8388       -3     
  Misses       1060     1060              
  Partials      374      374              

Impacted Files	Coverage Δ
internal/protocol/version.go	95.35% <ø> (-0.11%)	⬇️
conn_id_generator.go	89.29% <100.00%> (-0.37%)	⬇️

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