The official listing establishes release status. It does not establish whether a particular plugin, script, project, or processing result will work for your team. QGIS 4 has moved to Qt 6, as described in the QGIS 4.2 visual changelog. That is a confirmed technical change, not proof that every dependency built around your existing workflow is ready.

Do not read “current” as “best for every course” or “LTR” as “guaranteed compatible with every older project.” Those labels help you frame a decision. Your own inputs, plugins, and deliverables decide it.

Start with the plugins your study cannot do without. Make a short dependency register and check each item against its official plugin listing, author notes, and release information. Record what the plugin says about QGIS 4, when the information was updated, and whether the functions your team uses are covered.

A compatibility label is a screening signal. It may tell you that an author has declared a supported version range, but it cannot demonstrate that your study’s specific workflow succeeds. Even when a plugin loads, a key tool may behave differently, depend on another component, or produce an output your downstream script cannot consume.

Test the functions your research actually calls. Avoid approving a plugin because its menu appears or because a simple demonstration succeeds. If an essential plugin is unavailable or fails, document the missing capability and the proposed alternative. If the alternative changes the analysis, treat that as a methods decision requiring researcher approval—not as a routine software update.

Use a duplicate of an active project. Keep the established project untouched as a read-only baseline. QGIS documentation describes project and data formats, but successful file opening alone does not establish that a project’s references or results remain equivalent. See the QGIS file formats documentation when documenting what your deliverables contain.

Check the project as another researcher would receive it:

• Confirm each layer points to the intended dataset. Record whether paths are relative or absolute and whether data is stored locally, on shared storage, or elsewhere.
• Check that the expected layers render, and that joins, filters, labels, and symbology are present.
• Open layouts and inspect map extent, legend contents, labels, scale information, and export settings.
• Run expressions and project-specific scripts that affect analysis or presentation.
• Export the files your team hands to collaborators, then compare them with the baseline using checks relevant to the study.

A project that opens is only the beginning. Data paths can resolve to the wrong copy. A layout can render while a map frame or label differs. A script can complete but write to an unexpected location. Define what “same result” means for your research: for example, which attributes, spatial features, summary values, or exported layers must agree. Choose checks that reflect the claims you make from the data.

For reproducible handoff, preserve the baseline project, input-data descriptions, processing settings, and exported outputs. A second team member should be able to follow the record and reproduce the check without relying on the original operator’s memory. If that handoff fails, the migration is not complete even when the project appears usable on the machine where it was tested.

A geospatial result can depend on more than the project file. It may rely on a processing algorithm, an external provider, a coordinate operation, a data driver, or a script package. Make an inventory from the actual methods used in the study instead of assuming that a new release’s feature notes cover the whole chain.

The QGIS processing documentation explains the processing framework, while the QGIS 4.2 changelog records release changes. Use these sources to identify relevant boundaries. Do not infer that an older workflow produces identical results just because a newer release includes a related feature.

If a required step cannot be reproduced, stop the migration for that project. Keep QGIS 3.44.15 LTR as its working baseline while you investigate the provider, data, or script dependency. A blocked migration is a valid decision; quietly substituting a different algorithm without reviewing its effect is not.

A group needs a version policy, not just a preferred version on one person’s laptop. Agree which release is used for each project, who approves plugin updates, where project copies and baseline outputs are kept, and how a member reports a failed test. Write these decisions where collaborators can find them.

For a new course or study, a single tested version can reduce differences between team members’ environments. For mixed ongoing work, a documented dual track may be safer: keep established projects on their verified baseline while testing new work separately. The cost is extra maintenance. Someone must track which project belongs to which release, keep instructions current, and prevent accidental edits in the wrong environment.

QGIS configuration is also part of a reproducible setup. The official configuration documentation can help you identify settings that need to be recorded. Do not assume another member’s plugin setup, paths, or preferences match yours. Include the required setup in the handoff notes, and ask a colleague to repeat the test using those notes.

macOS validation boundary

If your work must run on macOS, follow the official QGIS macOS installation guide for the platform installation path, then test your own project. Installation support confirms that an installation route is documented; it does not certify your plugins, data paths, scripts, or processing results.

A remote Mac can help a lab that has no local Mac check its macOS workflow. Use a project copy and data that your institution permits you to use in that environment. Do not upload identifiable, restricted, or otherwise controlled research data unless your institution has approved the arrangement. Record the environment, project copy, test steps, observed outputs, and any limitations so the result is useful to the team. If you need to compare a temporary test environment with a locally managed machine, review the KVMNODE remote Mac options for research validation.

Use these conditions to make the decision and document why:

• If the project is new, every required plugin has a credible QGIS 4 support basis, the representative project and processing tasks pass, and a colleague can repeat the handoff, choose QGIS 4.2.3 for that project.
• If an essential plugin, script, provider, or coordinate operation is unverified or fails, keep the affected project on QGIS 3.44.15 LTR while you resolve the dependency.
• If new work passes but active projects do not, run both versions under a written project policy. Keep each project’s version, plugin set, and baseline outputs visible in its documentation.
• If the project opens but a key output has not been compared, do not call the migration complete. Repeat the test or return to the established baseline.

This is a project-level choice, not a lab-wide vote on which release is newer. A group can adopt QGIS 4.2.3 for a clean new workflow and retain QGIS 3.44.15 LTR for an active analysis whose dependencies have not passed verification.

Choosing a release for new work

Start with QGIS 4.2.3 when the required plugins and processing providers have clear support evidence and your own representative task passes. If a dependency is uncertain, establish the project on QGIS 3.44.15 LTR or keep the new-release trial isolated until the issue is resolved. The official release status helps you identify the versions to assess; it does not replace a project acceptance test.

Interpreting plugin compatibility labels

A compatibility label does not prove that a plugin’s functions work for your study. Check the author’s notes, install it in the target environment, and test the operations the project depends on. Record failures and alternatives. A plugin that loads but cannot complete a required task is not compatible for your workflow, regardless of how reassuring its listing appears.

Verifying an existing project

Copy the project and compare it with an untouched baseline. Check data references, layers, layouts, expressions, scripts, processing steps, and exported files. Define in advance which outputs matter to your research and how you will compare them. “It opens” is not a sufficient pass condition: the project must reproduce the results and deliverables your team relies on.

Running both releases in one group

A dual-track policy can preserve ongoing work while a new project is tested in QGIS 4.2.3. Assign each project to a release, document its plugins and dependencies, and retain its baseline outputs. Tell team members which environment to use before editing. Without those controls, parallel use can create confusion about the project state and make handoffs harder to reproduce.

Testing macOS without a lab Mac

Use a macOS environment to validate a project copy with approved sample or de-identified data, following the official installation guide. Test the functions your team needs rather than stopping after installation. A remote Mac provides a way to inspect the macOS workflow, but the result only applies to the tested project, dependencies, and data. Record any steps that could not be checked.

If your group relies on a shared Windows or Linux workstation, that setup may be convenient for its existing workflows, but it cannot by itself validate macOS behavior. Buying a Mac gives the lab a local machine, but it also means committing budget and managing hardware before you know whether the target project passes. For a short macOS acceptance run, a KVMNODE remote Mac can provide a real Mac environment through VNC, SSH, or a web console, with root access; it still requires your own project-level checks. You can review the available KVMNODE Mac access options. If you need a temporary validation environment, compare that route with your lab’s purchase and maintenance needs before choosing; do not move controlled data until your institution approves the handling plan. For QGIS 4.2.3, keep the trial on a project copy and retain QGIS 3.44.15 LTR as the fallback until the team has recorded a successful, repeatable acceptance result.