Changing Outbound SMTP server's 'From address'

Hi everyone,

Recently I had to modify the outbound SMTP server's 'from address' in SharePoint 2010 Central Admin from xx@abc.com to yy@def.com.

After making these changes I have performed an IISRESET.

I noticed that some of the custom workflows which deliver emails are not triggering emails now (though the workflows status show as completed).  So, do I need to republish all the workflows to reflect the smtp from address change ?

There is a big number of custom workflows in the web application !! Someone please advice!

Thank you!