iMacs upcoming in 2019?

Hi
I'm probably going to have to buy a new iMac this year - perhaps within 6 months. I don't really want to spend £5k+ on a iMac Pro and I have a large monitor so was thinking of getting a 21.5" version or something similar. However, does anyone know if Apple are intending to update the product line soon? I'd rather not splash out on buying one and then a new one becomes available within a couple of months?
Any info would be much appreciated.
Andy

The first thing I do is checked the Mac Buyers Guide to see where in the lifecycle each Apple product is. Some products like the iPhone are on a yearly refresh. On the Mac side, the MBP is nearly on a yearly refresh. while the iMac is slipping to about 2-3 years. The last versions came out in 2015 and 2017. If that cadence sticks, then we might be seeing an update in 2019 (usually latter part of the year).

But until Apple announces it, everything you read/see/hear is a rumor. Closer to the Apple events, a lot of the rumors end up being true, but this early in 2019 it's impossible to know.

Thanks mate, much appreciated!