https://www.forbes.com/sites/johnarcher/2019/03/09/lg-fixes-oled-tv-flashing-and-blocking-problems/amp/

The main points from the article :

• firmware version: 04.10.31

• it doesn't fix them 100% but enough that should rarely if ever notice them anymore

• C8, E8, W8 and G8 models get it by early April at the latest. The US and Europe will likely get the update first, with other territories following shortly after.

• B8 owners need to wait a little longer as the other sets using the A9 were prioritised over it but shouldn't be too long

• the firmware is LG specific so for other brands like Sony suffering from it you need to wait for them to bring their own firmware fix

Edit - they've updated the article:

[UPDATE: It seems that a few readers of the original version of the story below were taking my mentions of what were actually tiny qualifications about the update to mean that LG has somehow only delivered a partial fix for its OLED problems. This was not my intention; for me LG really has to all intents and purposes delivered a full solution with its software update.

I've therefore toned down/reduced the qualifications in the version of the article that now appears below, as I don't believe the original balance fairly reflected the results LG has achieved.]