How can I dump and restore db data from 3.6.8 to current 4.4 version?

Hi @priyatham_ik

MongoDB 3.6 series was out of support since April 2021 and thus it won’t receive any bugfixes or improvements anymore. Even if you can install a 3.6 series server, it’s best not to, and use a supported version instead. The oldest supported series is MongoDB 4.2 at this moment.

If you would like to get a fresh 4.4 series installation and move the data from the old deployment to the new one, Stennie posted a great answer here: Replace mongodb binaries all at once? - #3 by Stennie for a similar situation. Please see if the post answers your question.

Best regards
Kevin