iPhone free -> tier one upgrades (Main Bundle setting?)

My app has been free since the beginning, I uploaded a new version and set it to Teir 1 pricing.

People who updated got it for free for some reason, only new downloads by new users were charged.

Did I miss something in my main bundle to ensure that u开发者_如何转开发pgrades are not free?

It seems you cannot charge users for updates, so if they have downloaded your app once for free they will be able to update it also. I think the only option to introduce payments in free apps is to include in-app purchase in them.