Upgrade price from version 4.0 of iGuidance

Hello, I just got a trial version of iNav iGuidance 4.0. If I bought it and they released v5.0 in say 6 months, will I have to pay almost the entire price again? From what I've seen with earlier versions, upgraders pay almost 75% of the new price; is there a grace period like 6 months during which the upgrade is free?

I seem to find very good reviews from the website as well as other users. Hope I'll find it to be a nice program, worth keeping. The 10% off from this website is nice too I'll be using it entirely on a handheld, a Verizon HTC Touch. The card in it is 4 GB, plenty of room for the 1.4 GB of the program. I'll be using it along with a Delorme BT-20 Bluetooth puck.

Thx,
Roger

I think their free upgrade is 2 months and here is what I got from them:

Thanks much!!
Roger
I think I'll wait for ONC 8 to be released in May......

I have been using iGuidance for a couple of years now and still like it so I will probably wait until they announce the upgrade. I skipped this years upgrade since I bought my wife a gps unit for her car and have been using that.