I have been using Interspire since 2011. Lately, I've been hearing many people say that it has ran its course since updates are not included and many ISP's realize messages from from IEM and flag it as junk. Are you using Sendy and did you move from Interspire? If so, what has your impression been? I get a 10% open rate on an IEM account that isn't flagged and has a great reputation. If I send the same email on Vertical Response, I get 20-30% open rate. My SpamAssassin score is great. I'm not looking forward to moving from one to another but if I can increase my inbox rate, that will increase the number of people that open, click and buy from me. Let me know what your thoughts are with Sendy and using Interspire in 2015. PS - I do not know how to modify the headers. Maybe that would help??