Add "technology preview" note.

whatsnew.htm

@@ -32,7 +32,7 @@ For conditions of distribution and use, see <a href="files/is/license.txt">LICEN
 <p><a name="6.4.3"></a><span class="ver">6.4.3 </span><span class="date">(2025-05-03)</span></p>
 <ul>
   <li>Compiler IDE change: The editor now restores selections on undo and redo.</li>
-  <li>Inno Setup now includes a new command-line tool, ISSigTool.exe. This tool is designed to sign files using ECDSA P-256 cryptographic signatures. Compil32, ISCC, and ISCmplr use these signatures to verify a number of DLL files before loading them.<br />Note: ISSigTool.exe does not replace Microsoft's signtool.exe in any way and is in fact not related to Authenticode Code Signing at all.</li>
+  <li>Inno Setup now includes a new command-line tool, ISSigTool.exe. This tool is designed to sign files using ECDSA P-256 cryptographic signatures. Compil32, ISCC, and ISCmplr use these signatures to verify a number of DLL files before loading them. This is a &quot;technology preview&quot; that is subject to change (e.g., any signatures you create now may have to be recreated when upgrading to the next version).<br />Note: ISSigTool.exe does not replace Microsoft's signtool.exe in any way and is in fact not related to Authenticode Code Signing at all.</li>
   <li><i>Fix:</i> Autocomplete support for parameter names in the <tt>[Components]</tt> and <tt>[Dirs]</tt> sections was broken since 6.1.1.</li>
   <li><i>Fix:</i> Pascal Scripting support function <tt>Extract7ZipArchive</tt> which was introduced by 6.4.0 would fail with error 11 on older versions of Windows, at least Windows 8.1 and Windows Server 2016.</li>
   <li>Minor tweaks and documentation improvements.</li>