Why Upgrade to SQL Server 2016
SQL Server 2016 introduced improvements in performance, security, and analytics that make it a meaningful step forward from earlier versions. In-memory OLTP enhancements, PolyBase for querying external data, and always-encrypted columns are among the features that can justify an upgrade. Organizations running SQL Server 2012 or 2014 often find that moving to 2016 unlocks better query performance and stronger compliance controls, but the success of the move depends on careful planning and testing.
More from this site
Keep reading the latest coverage
Supported Upgrade Paths
Microsoft provides a defined set of upgrade paths into SQL Server 2016. Direct in-place upgrades are supported from SQL Server 2012 SP1 and later, as well as from SQL Server 2014. If you are running an older version, such as SQL Server 2008 R2, you will need to perform a migration rather than an in-place upgrade, which typically involves backing up databases, installing the new instance, and restoring the data. Cross-version upgrades to SQL Server 2016 are also possible through backup-and-restore or detach-and-attach methods, but each path has its own compatibility and downtime considerations.
Pre-Upgrade Compatibility Checks
Before starting an upgrade, run the SQL Server Upgrade Advisor or the newer Data Migration Assistant against your current instance. These tools flag deprecated features, breaking changes, and compatibility issues that could block the process. Pay close attention to query plans that rely on legacy cardinality estimator behavior, authentication mode changes, and any custom assemblies that may need recompilation. Reviewing the Microsoft documentation on discontinued features for SQL Server 2016 helps identify what will no longer be supported in the target version.
Licensing and Edition Considerations
Upgrading to SQL Server 2016 can shift your licensing posture, especially if you move to a newer edition such as Enterprise or Developer. SQL Server 2016 licensing supports both Server + CAL and Core-based models, and the choice affects cost and rights for high availability features like Always On Availability Groups. If you are using Software Assurance, upgrade rights are typically included, but organizations without SA should confirm their entitlement before proceeding. Licensing complexity increases when upgrading clustered or virtualized environments, so involve your licensing team early.
Performing the Upgrade
The in-place upgrade process for SQL Server 2016 begins with a full backup of system and user databases, followed by a system state backup if you are upgrading the default instance. Run setup.exe from the installation media and choose the Upgrade option. During the upgrade, the Database Engine Compatibility Level remains at the pre-upgrade setting by default, which preserves existing query behavior while allowing you to later adjust the compatibility level to take advantage of new cardinality estimator and optimizer improvements. Plan for a maintenance window, as the upgrade can take several hours depending on the size and number of databases.
Post-Upgrade Validation
After the upgrade completes, verify the SQL Server error log for any warnings or failures that occurred during the process. Run DBCC CHECKDB on all upgraded databases to confirm structural integrity. Test application connectivity, job schedules, and linked server configurations. Re-evaluate index fragmentation and update statistics, as the upgrade can change how the optimizer interprets legacy query plans. Monitor wait statistics and I/O patterns for a few days to confirm that performance has stabilized or improved.
Common Pitfalls and How to Avoid Them
- Skipping intermediate service packs: Upgrade directly to the latest SQL Server 2016 cumulative update rather than stepping through each release individually.
- Ignoring extended events and trace flag changes: Some trace flags are deprecated or behave differently in 2016; review your startup parameters.
- Underestimating downtime: Even in-place upgrades require downtime for backup, upgrade, and validation phases.
- Neglecting polybase and advanced analytics setup: If you plan to use PolyBase or R services, install and configure those components after the core engine upgrade.
When to Consider a Different Path
While SQL Server 2016 remains a stable and supported version, newer releases offer additional features and extended support timelines. Evaluate whether upgrading directly to SQL Server 2019 or 2022 better aligns with your long-term roadmap. If your environment is already complex, a side-by-side migration to a newer version may be cleaner than an in-place upgrade to 2016, particularly when you need to modernize hardware or operating system components at the same time.