NOT an event, will simply be announced via a Press Release as the SE2:
1.) Wide Color capture & display !
2.) 4.333" display at 326 PPI (Apple's native apps are Ready to Go, most 3rd-party apps will need an Update to support the new resolution; i.e., to be optimized for it).
3.) A10 chip + 3 GB DRAM !
4.) 12 Mpx Back camera from the iPhone 7 (& wide-angle of the 7 Plus) ... so, OIS !
5.) Being released now for three Reasons: i.) to try to steal some Thunder (from others) releasing products in mid-late August timeframe, and ii.) to cover themselves in-case the iPhone 8 Ramp-Up is worse than expected, due to the Tech Difficulties, and iii.) there is Fear within Apple that the iPhone 8's Home Button architecture may put-off many potential customers, and they want a viable / credible Fallback to offer !
Yes but not in August, in April 2018.