diff --git a/gui/chatblockmodel.cpp b/gui/chatblockmodel.cpp
index 9d70f47..9b70b55 100644
--- a/gui/chatblockmodel.cpp
+++ b/gui/chatblockmodel.cpp
@@ -194,21 +194,27 @@ QString ChatBlockModel::highlightCode(const QString &code, const QString &langua
 QString ChatBlockModel::renderMarkdown(const QString &markdown) const
 {
     // Pre-process: render <system-user-interruption> blocks as styled boxes.
+    // Manual global-match loop instead of replace-with-lambda, which requires
+    // Qt 6.5+ and isn't available on all target systems.
     static const QRegularExpression interruptionRe(
         R"(<system-user-interruption>\n([\s\S]*?)\n</system-user-interruption>)");
-    QString processed = markdown;
-    processed.replace(interruptionRe, [](const QString &match) -> QString {
-        // Extract content between the tags (after opening "<system-user-interruption>\n"
-        // and before trailing "\n</system-user-interruption>").
-        const int start = QStringLiteral("<system-user-interruption>\n").size();
-        const int end = match.size() - QStringLiteral("\n</system-user-interruption>").size();
-        const QString content = match.mid(start, end - start).toHtmlEscaped();
-        return QStringLiteral(
-            "<div style=\"background:#fff8e1;border:1px solid #ffca28;"
-            "border-radius:4px;padding:8px;margin:8px 0;white-space:pre-wrap;\">"
-            "\u26A0\uFE0F <strong>User interruption</strong>\n") + content +
-            QStringLiteral("</div>");
-    });
+    QString processed;
+    {
+        int cursor = 0;
+        auto it = interruptionRe.globalMatch(markdown);
+        while (it.hasNext()) {
+            const auto match = it.next();
+            processed += markdown.mid(cursor, match.capturedStart() - cursor);
+            const QString content = match.captured(1).toHtmlEscaped();
+            processed += QStringLiteral(
+                "<div style=\"background:#fff8e1;border:1px solid #ffca28;"
+                "border-radius:4px;padding:8px;margin:8px 0;white-space:pre-wrap;\">"
+                "\u26A0\uFE0F <strong>User interruption</strong>\n")
+                + content + QStringLiteral("</div>");
+            cursor = match.capturedEnd();
+        }
+        processed += markdown.mid(cursor);
+    }
 
     static const QRegularExpression fenceRe(
         R"(```([A-Za-z0-9_+.-]*)[^\n]*\n([\s\S]*?)\n```(\n|$))");