<ul>
<li>I encountered this issue after upgrading from fedora 38 to 40
<blockquote>
WARNING: database "template1" has a collation version mismatch DETAIL: The database was created using collation version 2.37, but the operating system provides version 2.39.
</blockquote>
</li>
</ul>
Solution
<ol>
<li>connect to the specific database showing the error. In most cases all the databases,
</li>
<li>reindex the database
</li>
<li>refresh the collation
</li>
</ol>
<pre><code class="lang-bash">/c database1
&gt; REINDEX DATABASE database1;
&gt; ALTER DATABASE database1 REFRESH COLLATION VERSION;
</code></pre>

* I encountered this issue after upgrading from fedora 38 to 40
    
    > WARNING: database "template1" has a collation version mismatch DETAIL: The database was created using collation version 2.37, but the operating system provides version 2.39.
    

Solution

1. connect to the specific database showing the error. In most cases all the databases,
    
2. reindex the database
    
3. refresh the collation
    

```bash
/c database1
> REINDEX DATABASE database1;
>  ALTER DATABASE database1 REFRESH COLLATION VERSION;
```

Resolve postgres collation Mismatch