Sony has rolled out June 2018 Android security patch to Sony Xperia XA2 and XA2 ultra devices. Both these models have received March 2018 security patches during April month. Update carries the build number 50.1.A.10.40. Changelog of the update does not provide any other info other than security patches.
Updates can be manually verified heading to Settings-> about phone-> Software update. The update is rolled out as an OTA and it will take a couple of days to hit all the devices.