iphone2g-no40 In an e-mail to a German customer, Steve Jobs confirmed what most of us surmised last week: There will be no iPhone OS 4.0 support for original 2G iPhone owners.

At last week’s iPhone OS 4.0 announcement, Apple let iPhone 3G and second-generation iPod touch owners know that those devices will not support multitasking, although they will support other new features.

For owners of the nearly three-year-old original iPhone, it looks like iPhone OS 3.1.x will be the end of the line in terms of official OS updates. Jobs didn’t explain why Apple is no longer going to offer software updates for the original iPhone, though we suspect it’s part of a plan to phase out the product line.

While many iPhone 3G owners have bristled over the lack of multitasking support, the truth is — from a strictly hardware standpoint — the iPhone 3GS is much more advanced. It not only uses a much faster and newer ARM CPU, it also has twice as much memory (RAM) and a significantly better graphics processor than the the original iPhone and the iPhone 3G.

The original iPhone and the iPhone 3G are actually nearly identical specification-wise, save some changes to form factor, battery and the addition of GPS and 3G capabilities to the iPhone 3G. One special note about the original iPhone is that it is still the easiest device to both “jailbreak” and unlock, which might be another reason Apple doesn’t want to continue to support it with software updates.

For angry iPhone 2G owners, we feel your pain. However, at least you got nearly three years of updates. My G1 was basically over the hill within a year of purchase. Do you still have an original iPhone? Does the lack of 4.0 support entice you to upgrade? Let us know!