Also known as: TR, TR Level
IBM's periodic incremental update to a given IBM i release, delivering new features and fixes without requiring a full operating system upgrade.
A Technology Refresh (TR) is IBM's mechanism for delivering new features and capabilities into an existing IBM i release incrementally, without requiring a full version upgrade. Each IBM i release receives a series of TRs over its supported lifetime; an IBM i shop's current "TR level" is a routine thing to check both before a migration and as part of ongoing maintenance.
Staying current on TRs is different from staying current on hardware. A well-maintained system can be behind on hardware generation while current on TR level, or the reverse, which is why a migration assessment checks both independently.