sqlfingers.com: SQL Server 2016 Ends in July. Here's What Will Break.

Wednesday, February 4, 2026

SQL Server 2016 Ends in July. Here's What Will Break.

SQL Server 2016 goes end of life on July 14, 2026. That's five months from now.

If you're still running 2016 in production, you're not alone. Based on one vendor's assessment, SQL Server 2016 is still 20% of production deployments. That's a lot of DBAs who need to get moving pretty much now.

Here's the problem: Many of those upgrades are going to break. Not because the engine upgrade fails, but because SQL Server 2025 changed the defaults. Silently. In ways that won't show up until you're already committed.

The Deadline

After July 14, 2026:

No more security patches
No more support calls
No longer compliant

You can buy Extended Security Updates (ESU) for up to three more years. But ESU only covers critical security patches — no bug fixes, no features, and the cost increases each year. It's a holding pattern, not a solution.

The real solution is to upgrade. And if you're planning on 2016 to 2025, you're about to learn that Microsoft quietly raised the security baseline while we weren't looking.

What Changed in 2025

SQL Server 2025 ships with MSOLEDBSQL 19, and its defaults are different from what you've been using. The new provider enforces:

Encrypt = True by default
TrustServerCertificate = False by default
Strict certificate chain validation

Translation: if your environment uses self-signed certificates, internal CAs that aren't in the trust store, or no encryption at all — connections will fail. Unavoidably.

This affects linked servers, replication, log shipping, and any application still using legacy connection strings. The old SQL Native Client (SQLNCLI) used to suppress or ignore these errors. MSOLEDBSQL 19 does not.

Three Things That Will Break

1. Linked Servers

If you configured linked servers using SQLNCLI (which was the default for years), they'll fail after upgrade with errors like:

Msg 7303, Level 16, State 1
Cannot initialize the data source object of OLE DB provider "MSOLEDBSQL" 
for linked server "LinkedServerName".

TCP Provider: The certificate chain was issued by an authority that is not trusted.

The fix is to either install proper certificates or reconfigure the linked server with TrustServerCertificate=yes — which defeats the security improvement but at least gets you running.

2. Replication

If your publisher is SQL Server 2025 and your distributor is remote without a trusted certificate, replication will fail. You'll see:

OLE DB provider "MSOLEDBSQL19" for linked server "repl_distributor" returned message 
"Client unable to establish connection".

Msg -2146893019, Level 16, State 1
SSL Provider: The certificate chain was issued by an authority that is not trusted.

This hits transactional, snapshot, peer-to-peer, and merge replication. Replication Monitor in SSMS will also fail if it can't validate the certificate chain.

The workaround (if you can't deploy trusted certificates yet):

EXEC sp_changedistributor_property 
    @property = N'trust_distributor_certificate', 
    @value = N'yes';

3. Full-Text Search

SQL Server 2025 introduces a new full-text index version. Existing catalogs stay on version 1 (unchanged since 2005) unless you manually upgrade them. After the engine upgrade, your full-text queries will fail:

Msg 30010, Level 16, State 2
An error has occurred during the full-text query. Common causes include: 
word-breaking errors or timeout, FDHOST permissions/ACL issues, 
service account missing privileges, malfunctioning IFilters...

The fix is to rebuild your full-text indexes — or if you need to keep using the old version temporarily:

ALTER DATABASE SCOPED CONFIGURATION SET FULLTEXT_INDEX_VERSION = 1;

But version 1 is deprecated. This is a temporary workaround, not a long-term solution.

And if you're using Database Mail, there's another bug that forced Microsoft to pull back a fix. Be sure to check Database Mail status before you upgrade.

What to Check Now

Before you upgrade anything, audit these:

Component	What to Check
Linked Servers	Provider (SQLNCLI vs MSOLEDBSQL), encryption settings, certificate trust
Replication	Remote distributor topology, certificate chain on all nodes
Log Shipping	Remote monitor server, same TLS requirements as linked servers
Full-Text Indexes	Current index version, rebuild time estimates
Connection Strings	Legacy providers, missing Encrypt/TrustServerCertificate params
SSIS Packages	Execute SQL Task / SMO tasks using Dts.Runtime API — update references, rebuild

Run this to find your linked server providers:

SELECT 
    s.name AS linked_server,
    s.provider,
    s.data_source
FROM sys.servers s
WHERE s.is_linked = 1;

Any row showing SQLNCLI or SQLNCLI11 needs attention before upgrade.

The Upgrade Path

SQL Server 2025 supports direct in-place upgrades from 2016. That doesn't mean it's easy — it means it's possible.

The safe approach:

Audit linked servers, replication, full-text, and SSIS before touching anything
Deploy certificates or workarounds for each component
Test in a non-production environment — not just the upgrade, but every downstream connection
Plan for full-text index rebuilds (this takes time on large catalogs)
Schedule the production upgrade with sufficient buffer time for surprises

If you haven't started yet, you need to get moving. Five months sounds like plenty of time until you recognize that your replication topology spans three datacenters and nobody knows where the certificates are.

The Bottom Line

The engine upgrade isn't the hard part. Discovering what breaks is.

Microsoft raised the security baseline in 2025. That's a good thing — in the long run. But if you're jumping from 2016, you're skipping several versions of gradual tightening and jumping right into the deep end.

Need help migrating before July? We specialize in SQL Server 2016→2025 upgrades with zero downtime.

SQL Server Consulting