LG 55EC9300 Software Update 5.00.04 and 5.00.15
(Update: LG 55EC9300 update 5.00.15 released to fix issue with 5.00.04 noted below.)
Sunday night (Sept. 13th) a software/firmware update 5.00.04 for LG 55EC9300 OLED HDTV was available via network update, but as of Monday Sept. 14th it wasn't appearing anymore. (Update: LG 55EA9300 owners reported 5.00.04 was available again on Sept. 17th.)
However some LG 55EC9300 users that updated to v5.00.04 later reported after some period of use apps quit with a message "This App will now restart to free up memory". I heard LG Support is aware of that and the 5.00.04 update may be pulled until a fix is released. Later noted this may be due to having "Simplink" On. (That's LG's name for HDMI control.) Until this is fixed, if you updated to 5.00.04 and have the App restarting problem, see if Simplink is enabled. (If you're using ARC, it requires HDMI control enabled in both TV & AVR, so you'll lose that by turning it off.)
The 5.00.04 update was slated for Sept. 21st, to add webOS 2-like features to the 2014 model which shipped with WebOS 1. Although the 5.00.04 update does apply some webOS 2 looking features, the version after 5.00.04 update was listed as WebOS 1.40-2504. (The 5.00.15 update is WebOS 1.40-2507.) The 55EC9300's previous 4.45.05 firmware had WebOS 1.3.3-3247.
(As of late October 2015, the USA LG 55EC9300 support page doesn't list the 5.00.15 update for download. They did have 4.41.39, 4.41.30, and 03.23.32 there. Although they have older versions for download (large files), I don't think you can downgrade from a later version.)