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 								<h3><a href="https://pki.zhanganjun.com">PKI Services</a></h3>
 								<p>PKI system supports the generation, issuance, distribution, revocation, administration, and management of public/private cryptographic keys that are contained in CA-signed X.509 Certificates.</p>
 							</article>
+							<!--
 							<article class="col-6 col-12-xsmall work-item">
 								<a href="images/connect4.jpg" class="image fit thumb"><img src="images/connect4.jpg" alt="" /></a>
 								<h3><a href="https://github.com/CitizenBeta/Connect4">Connect 4</a></h3>
 								<p>A Python implementation of the classic text-based Connect 4 game (If you cannot access GitHub, <a href="https://repo.zhanganjun.com/Connect4">click here</a>).</p>
 							</article>
-							<article class="col-6 col-12-xsmall work-item">
-								<a href="images/certtool.jpg" class="image fit thumb"><img src="images/certtool.jpg" alt="" /></a>
-								<h3><a href="https://github.com/CitizenBeta/CertTool">CertTool</a></h3>
-								<p>CertTool provides the easiest and the safest way to trust our certificates (If you cannot access GitHub, <a href="https://repo.zhanganjun.com/pki/CertTool/">click here</a>).</p>
-							</article>
+							-->
 						</div>
 					</section>
 
@@ -65,7 +62,7 @@
 					</ul>
 					<ul class="copyright">
 						<li>&copy; <span id=year><script>document.getElementById("year").innerHTML=(new Date).getFullYear()</script></span> Zhang Anjun. All rights reserved.</li>
-						<li><a href="https://github.com/CitizenBeta/Homepage/releases/tag/v3.9">v3.9</a></li>
+						<li><a href="https://github.com/CitizenBeta/Homepage/releases/tag/v3.9.1">v3.9.1</a></li>
 						<li><a href="https://zaj.statuspage.io/">System Status</a></li>
 						<li><img src="https://static.zhanganjun.com/common/beian.png" style="width:16px;"/><a href="https://beian.mps.gov.cn/#/query/webSearch?code=11010802045392" rel="noreferrer" target="_blank">京公网安备11010802045392号</a></li>
 						<li><a href="https://beian.miit.gov.cn" target="_blank">京ICP备2025105392号-2</a></li>