Splunk UBA will be supported for most current version plus the prior two major or minor releases OR 1 year from License key delivery whichever is longer.
For example, current supported versions are the most current version plus 2 prior releases (4.0.0, 3.3.x and 3.2.x). If v4.1 is released today, v3.2.x will reach EOL. However, if you have purchased license on v3.2.x eight months ago, then you have for an extra 4 months of support on v3.2.x. Your license for UBA ensures at least 1 year of support from the date it was issued.