New York : Boeing Co said on Monday it planned to submit a proposed software enhancement package for the grounded 737 MAX in "the coming weeks" after the company had previously said it planned to deliver the fix for government approval by last week. The company on Monday confirmed a statement from the Federal Aviation Administration that it would submit the upgrade later than previously announced. "We are working to demonstrate that we have identified and appropriately addressed all certification requirements and will be submitting for FAA review once completed in the coming weeks," Boeing said. "We will take a thorough and methodical approach to the development and testing of the update to ensure we take the time to get it right." More than 300 Boeing 737 MAX jets have been grounded worldwide after two crashes - in Indonesia in October and in Ethiopia last month - killed nearly 350 people.