Filing obligations for draft and offer documents require lead manager certifications, due diligence and updated filings before registrar submission. Regulation 186 requires issuers to file three copies of the draft offer document with the Board through lead manager(s), furnish soft copies, and file updated drafts highlighting changes before registrar filing. Lead manager(s) must submit engagement evidence, prescribed due diligence certificates at specified stages, certify incorporation of the Board's observations, and provide a due diligence form when material developments are publicly disclosed. Updated or fresh drafts must be filed for changes to Schedule XVI matters with applicable fees, and offer documents must be promptly filed with the Board and stock exchanges after registrar submission.