Assume for the sake of open-source privileges that you are switching from Microsoft Outlook to Mozilla Thunderbird. Your OST needs to be exported to the MBOX file format for Thunderbird. To guarantee a seamless transfer of all your emails, attachments, and folders to Thunderbird, this is required. Thunderbird features are guaranteed to work to their fullest extent because the data integrity is preserved without any loss or disruption. Several solutions, including an OST to PST Converter tool to convert OST to MBOX format, will be covered in this comprehensive blog.
https://www.data-recovery-solutions.com/blog/convert-ost-to-mbox-format/