Assuming an upgrade is a like-for-like change
One of the most common pitfalls is treating a Drupal upgrade as a simple version bump. Major upgrades often include significant changes to architecture, theming, and module ecosystems. Drupal 7 to Drupal 9/10, for example, is a rebuild rather than an in-place upgrade, and even Drupal 9 to 10 can involve important compatibility work. Plan the project as a structured migration with defined milestones, not a quick patch.
Skipping a full audit of modules, themes, and custom code
Upgrades fail most often because of what sits around Drupal core: contributed modules, custom modules, and bespoke themes. Before any work begins, catalogue what you have, why it exists, and whether it is still needed. Identify modules that are no longer maintained, replaced by core functionality, or incompatible with your target version. For custom code, check for deprecated APIs, outdated libraries, and any tight coupling to old data structures.
Not aligning the upgrade with business goals
It is easy to focus purely on technical compatibility and miss the bigger picture. An upgrade is an opportunity to remove legacy features, streamline content workflows, improve performance, and strengthen security posture. Define what “success” looks like for the organisation: faster publishing, better search, improved accessibility, or reduced maintenance overhead. Without clear goals, projects drift, and stakeholders lose confidence.
Underestimating content and data migration complexity
Content is rarely as simple as nodes and images. Real-world Drupal sites often include complex field configurations, multilingual content, embedded media, taxonomy structures, redirects, and third-party integrations. Migration needs careful mapping and repeatable processes, especially when content editors must continue working while the upgrade is underway. Create a migration plan that covers content types, fields, media, user accounts, roles, permissions, and URL structures, then test it with realistic data volumes.
Neglecting redirects and URL continuity
Changing paths without a redirect strategy is a direct route to broken bookmarks, lost search rankings, and poor user experience. Preserve existing URLs wherever possible, and where changes are unavoidable, implement 301 redirects with a clear mapping. Pay special attention to top-performing pages, campaign landing pages, and any URLs used in printed materials or external partner sites.
Failing to account for SEO and analytics from day one
SEO is not something to “fix after launch”. Upgrades can inadvertently remove critical metadata, alter indexation rules, or change internal linking structures. Confirm that titles, meta descriptions, canonical tags, structured data, XML sitemaps, robots rules, and hreflang (if relevant) are handled correctly. Also ensure analytics and conversion tracking are preserved, including consent management and event tracking. Compare pre- and post-upgrade performance using consistent measurement windows.
Overlooking accessibility and front-end regressions
A theme rebuild or refresh can introduce accessibility issues even when the site looks visually improved. Ensure components meet WCAG expectations, including keyboard navigation, focus states, colour contrast, form labelling, and meaningful error messages. Test templates across devices and browsers, and validate that core user journeys remain smooth. Accessibility checks should be part of your definition of done, not a late-stage review.
Not creating a realistic testing plan
Drupal upgrades touch many moving parts, so superficial testing is risky. Build a testing checklist that covers functional behaviour, editorial workflows, permissions, search, forms, email delivery, media handling, caching, and integrations. Include performance testing (especially for logged-in areas), as well as security checks for configuration exposure and access controls. Where possible, automate regression testing for key journeys to reduce human error and speed up iteration.
Ignoring performance and caching considerations
Performance can improve significantly with a modern Drupal stack, but only if the environment and configuration are right. Review PHP versions, database configuration, opcode caching, and caching layers such as Redis or Varnish where appropriate. Confirm that Drupal caching is configured correctly, that dynamic pages are not accidentally cached, and that cache invalidation behaves as expected. Also ensure images are optimised, CSS and JavaScript are aggregated sensibly, and logging is not excessive in production.
Not reviewing security and permissions during the upgrade
An upgrade is the ideal time to tighten security. Reassess roles and permissions, remove unused accounts, enforce strong authentication policies, and check that administrative routes are protected appropriately. Review file permissions, private file handling, and any custom endpoints. Ensure the site is running on supported versions of PHP and dependencies, and that update processes are in place for core and contributed modules once live.
Forgetting about email, forms, and third-party integrations
Forms and integrations are frequent sources of post-launch surprises. Confirm that webforms, transactional emails, SMTP settings, CRM connections, payment gateways, search services, and marketing tools continue to function. Test with real-world scenarios: file uploads, conditional logic, confirmation emails, and spam protection. Where integrations rely on API keys or IP allowlists, plan changes ahead of time to avoid downtime.
Rushing the go-live plan and rollback strategy
A smooth launch is rarely accidental. Prepare a clear cutover plan that includes content freeze windows (if required), final migration runs, DNS and certificate checks, cache warm-up, and post-launch verification. Decide in advance what constitutes a rollback scenario and how you will execute it. Keep stakeholders informed with timelines and responsibilities so the launch is controlled rather than reactive.
Not planning for ongoing maintenance after the upgrade
Upgrading Drupal is not the finish line. Establish a maintenance routine for security updates, monitoring, backups, and performance reviews. Document how the site is built, how deployments work, and how editors should use new features. A well-maintained Drupal site remains secure, fast, and cost-effective for years, while a neglected one quickly accumulates risk and technical debt.
Take the next step
If you are planning a Drupal upgrade and want it delivered with clear planning, robust testing, and minimal disruption, explore how Enbecom can help with Drupal development, security, hosting, and ongoing support. Visit https://www.enbecom.net to find out more and discuss your requirements.