Hi @kabOOmShankar,
Since you upgraded to a WHOOP MG membership and have a leftover WHOOP 5.0 strap from your trial, there is no requirement to return the 5.0 strap. WHOOP does not require hardware returns when upgrading devices or memberships.
You can keep your WHOOP 5.0 strap, and if you like, you can pass it on to a friend or family member who can activate it with a new membership. This is part of WHOOP’s upcycle program to promote sustainable reuse.