TEST C250: Why Is Subcutaneous vs Intramuscular Injection Still Debated?

[Howard112]

I've noticed more discussions recently comparing subcutaneous and intramuscular administration of Testosterone Cypionate.
Some recent medical publications suggest both approaches may be appropriate in certain situations, while many older discussions seem to assume intramuscular injection is the only option.
For anyone who follows current TRT research:

• Has the evidence changed over the last few years?
  
• Are current clinical guidelines discussing both methods?
  
• Any good journal articles worth reading?
  

I'm mainly interested in what current research says rather than personal preferences.