Retcons are valuable things in Champions Online, and they are used only with care, as their effects can be far-reaching and are assured to be constant for quite some time. (This marks a major point of divergence between Champions Online and most current comic books, but we'll leave that to one side for the time being.) So it's a bit significant when Cryptic announces that everyone will be getting a free retcon on October 27th, just in time for the Blood Moon event to kick off in full swing.
Cryptic's official explanation is that the free retcon comes as a result of server troubles over the weekend, and is their little way of extending an olive branch to the community. It does come with a bit of a caveat, however -- if you've been banking up your previous free retcon in anticipation of needing it later, they won't stack. You just get the one free.
But that's not such a big issue, when you get right down to it -- you can use the retcon if you need it, and start enjoying the zombie-smashing fun. And if you aren't already playing, perhaps now is a fine time to mention that there's a free weekend starting on Friday?