If I DON'T upgrade....will I...

[LaCosta]

If I do not download iOS10 or any future iOS......will my current iOS continue to receive security and other mission critical updates?

 

[KALLT]

No, nothing. iOS 9 is now end of life.

 

[cola79]

No, nothing. iOS 9 is now end of life.

If the security problem is big enough, he might get one. Wasn't it so some time earlier or do I just think it was?

 

[KALLT]

If the security problem is big enough, he might get one. Wasn't it so some time earlier or do I just think it was?

It happened exactly three times, a long time ago. iOS 3 had a post-EOL update to prevent jailbreaking, iOS 6 had two updates to assure normal usage of the device. In the first case it was an expired certificate that prevented users from using FaceTime, in the second one it was a bug in SSL that prevented connections to certain secured websites (which meant that some websites could not be accessed). Although strictly a security issue, it was likely done to make sure that people could still use their phones for browsing. In the case of iOS 6, these updates were only signed for devices that were unsupported by iOS 7.

 

[sbailey4]

If the security problem is big enough, he might get one. Wasn't it so some time earlier or do I just think it was?

Nah doubtful. If the device is eligible to run the latest version you wont. Devices that cant run iOS 10 "may" but only in extreme case. Past updates would have been because the devices were not eligible to run the newest iOS and some critical patch was needed.