Like the Apex One server, Update Agents also use component duplication when downloading components. See Apex One Server Component Duplication for details on how the server performs component duplication.
The component duplication process for Update Agents is as follows:
The Update Agent compares its current full pattern version with the latest version on the update source. If the difference between the two versions is 14 or less, the Update Agent downloads the incremental pattern that accounts for the difference between the two versions.
If the difference is more than 14, the Update Agent automatically downloads the full version of the pattern file.
The Update Agent merges the incremental pattern it downloaded with its current full pattern to generate the latest full pattern.
The Update Agent downloads all the remaining incremental patterns on the update source.
The latest full pattern and all the incremental patterns are made available to agents.