Hi,
If you update and email template then all of the email that are using that template will go into 'Draft' version. You will need to re-approve all of these emails to see the updated email template.
You can do a 'bulk approve' by doing the following:
1: Go to design Studio
2: Click on 'Emails' (you'll now see all of your emails in Marketo listed here
3: Sort emails either by template or 'last updated'. I tend to use 'Last updated' as any email template change will 'update' all he emails using the template.
4: Using the Shift or CTRL key select all the emails using the updated template (you might have to do this page by page if there are loads)
5: On the top bar (under the tabs), click Email Actions>Approve Drafts - this will approve all of the draft emails selected in one go.
6: Go to Marketing Activities and you should be able to select an email and see the changes,
Hope this helps :-)
Juli