The nf-core roadmap for adopting the new Nextflow syntax
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Upcoming changes to Nextflow syntax

During the Nextflow Summit 2025, Ben Sherman introduced all the changes that are comming to Nextflow with the next versions. There is also a Nextflow blogpost talking about the changes that we will start seeing within the next Nextflow releases.

As always, in nf-core, we try to keep up-to-date with the latest Nextflow features and standards. For this reason, we have thought of the best way to deliver all these goodies to all our nf-core pipelines through template updates, but making it as easy as possible for pipeline maintainers to adopt them.

nf-core syntax adoption

The syntax changes will be introduced into Nextflow gradually, and we will do so in nf-core:

For every one of the changes, we will wait until the following release to adopt the changes in nf-core.

First, we will allow the new functionalities in the pipeline template, and nf-core linting will warn you if you are using the old syntax (without failing!).
Then, we will switch linting to a failure for old Nextflow syntax, making it mandatory to update your pipeline to the new one.

Here is a detailed roadmap of the incoming changes:

Line diagram outlining the different planned adoptions

These are the changes that will be (or have been) included in each Nextflow version:

Nextflow v25.04:
- topic channels
- workflow outputs (preview)
Nextflow v25.10:
- workflow params
- workflow outputs
- workflow onComplete: and onError: section
- type annotations
- typed process inputs/outputs
Nextflow v26.04:
- record types
- dataflow
- typed processes
- strict type checking

In nf-core, we will adopt these changes in the following timeline:

4th quarter 2025:
- Topic channels are allowed (nf-core tools version 3.5.0 released in November 2025)
2nd quarter 2026:
- Topic channels are mandatory
- Strict syntax is mandatory
- Static types and records are allowed
- New process syntax is allowed
4th quarter 2026:
- Static types and records are added to the pipeline template
- New process syntax is added to the pipeline template
2nd quarter 2027:
- Static types and records are mandatory
- New process syntax is mandatory

How to adopt all these changes in a pipeline

In order to make it easier for maintainers to adopt Nextflow syntax changes, we have implemented a couple of new changes to the pipeline template sync process:

The template sync PRs that are opened to pipeline repositories with every new nf-core/tools will remain open, even if a new tools release is made.
- This will allow you to choose if you want to add these changes one at a time, or wait until you receive multiple tools releases and do a single template update in bulk.
- We recommend that you keep up to date with template updates, to have smaller changes and make the update and review process smother.
All sync PRs will include a direct link to the nf-core/tools release blog post.
- This blog posts include a description of the changes made in this release, and a list of tips on how to implemente these changes to your pipeline, as well as guidance on how to resolve merge conflicts.