h3. Multi-file docker image collections
Typically a docker image collection contains a single @.tar@ file at the top level. Handling of atypical cases has changed. If a docker image collection contains files with extensions other than @.tar@, they will be ignored (previously they could cause errors). If a docker image collection contains multiple @.tar@ files, it will cause an error at runtime, "cannot choose from multiple tar files in image collection" (previously one of the @.tar@ files was selected). Subdirectories are ignored. The @arv keep docker@ command always creates a collection with a single @.tar@ file, and never uses subdirectories, so this change will not affect most users.
h3. Multi-file docker image collections
Typically a docker image collection contains a single @.tar@ file at the top level. Handling of atypical cases has changed. If a docker image collection contains files with extensions other than @.tar@, they will be ignored (previously they could cause errors). If a docker image collection contains multiple @.tar@ files, it will cause an error at runtime, "cannot choose from multiple tar files in image collection" (previously one of the @.tar@ files was selected). Subdirectories are ignored. The @arv keep docker@ command always creates a collection with a single @.tar@ file, and never uses subdirectories, so this change will not affect most users.