It's been upgraded twice, once when it got weather sealing and IS, once again when it got better glass and better IS.
What would an upgrade bring that you don't have available already? Canon NEVER upgrades it's lenses for free.
Enjoy the excellent value non-is whilst you can still get it. I have one and it's brilliant value.
Canon 7D, T3i, EOS M, EOS 3, GoPro HD Hero & Hero 2, powershot sx230 hs, Canon 70-200 f2.8 L, Canon 100mm f2.0, Sigma 70mm f2.8 Macro, Canon 50mm f1.8, Canon 22mm f2.0, Sigma 18-50 f2.8, Tokina 11-16 f2.8, Lensbaby Composer, Holga HL