I think I found the solution here: https://nf-co.re/docs/tutorials/migrate_to_topics/update_modules Hei, I updated the nf-core modules in a pipeline and I am a bit confused about versions. I get this error

Reading in files from folder
Initializing channels
[-        ] process > CUSTOMCAGE:PREPROCESSING:CAT_FASTQ -
ERROR ~ No such variable: Exception evaluating property 'versions' for nextflow.script.ChannelOut, Reason: groovy.lang.MissingPropertyException: No such property: versions for class: groovyx.gpars.dataflow.DataflowBroadcast

and I understand that it is because the output name changed

output:
    tuple val(meta), path("*.merged.fastq.gz"), emit: reads
    tuple val("${task.process}"), val("cat"), eval("cat --version 2>&1 | head -n 1 | sed 's/^.*coreutils) //; s/ .*\$//'"), emit: versions_cat, topic: versions

_what I am not sure about is if i should use the

versions_cat

or there is a way to keep using

versions

in the subpipelines?_ this works, but am I intended to change it or the verions topic is accessible?

ch_versions = ch_versions.mix(CAT_FASTQ.out.versions_cat)

Ideally, you should update the template to version >=3.5.0 and then get rid of the

versions

output and the

ch_versions

channel altogether.

Thanks for your reply! I think some modules are not updated yet while others are, so I think I have a mixed solution in the pipeline. I will look into this a bit more.

The template allows for mixed use. Just keep mixing into the old

ch_versions

channel as usual in modules that emit a

versions

.

And help make PRs to the modules repo for the ones that are missing!