Form-1B and 61 not required for conversion. Now you have to file form-62 with ROC along with SRN no. of form-23.
Annexure of form 62 are==
1. Signed statement in lieu of prospectus (SLP).
2. Other annexures of SLP like notice of GM, certifies true copy of GM resolution, list of directors, list of shareholders, balance sheet of last 3 years and appointment of statutory auditors documents etc.