I am very disappointed in this. I have only been an Open-E customer for 120 days, if I had realized that there was going to be a cost associated with keeping my virtually NIB product up to date I might have waited.
Also, I checked the comparison, you only offer 6 new features. This doesn't look like a "major upgrade" to me. I accept that the cost of doing business is increasing, and I also accept that it might be necessary to pay for your support contracts. But if those contracts are current then I don't see any point in charging for upgrades.
Also, you might offer free upgrades for anyone who bought the product recently (since 1/1/2009 for example).