Add regression warning to prevent users from upgrading to 1.26.0
diff --git a/news/2020/10/06/release-1.26.0/index.html b/news/2020/10/06/release-1.26.0/index.html
index 6329e59..dfd02a0 100644
--- a/news/2020/10/06/release-1.26.0/index.html
+++ b/news/2020/10/06/release-1.26.0/index.html
@@ -141,6 +141,10 @@
is pleased to announce
<a href="/docs/history.html#v1-26-0">Apache Calcite release 1.26.0</a>.</p>
+<p><strong>Warning:</strong> Calcite 1.26.0 has <strong>severe</strong> issues with <code class="highlighter-rouge">RexNode</code> simplification caused by <code class="highlighter-rouge">SEARCH operator</code> (
+wrong data from query optimization, <code class="highlighter-rouge">NullPointerException</code>), so use 1.26.0 for development only,
+and beware that Calcite 1.26.0 would corrupt your data.</p>
+
<p>This release comes about two months after 1.25.0 and includes more than 70 resolved
issues, comprising a lot of new features and bug-fixes. Among others, it is worth highlighting the following.</p>
diff --git a/news/index.html b/news/index.html
index b050aca..f90170f 100644
--- a/news/index.html
+++ b/news/index.html
@@ -146,6 +146,10 @@
is pleased to announce
<a href="/docs/history.html#v1-26-0">Apache Calcite release 1.26.0</a>.</p>
+<p><strong>Warning:</strong> Calcite 1.26.0 has <strong>severe</strong> issues with <code class="highlighter-rouge">RexNode</code> simplification caused by <code class="highlighter-rouge">SEARCH operator</code> (
+wrong data from query optimization, <code class="highlighter-rouge">NullPointerException</code>), so use 1.26.0 for development only,
+and beware that Calcite 1.26.0 would corrupt your data.</p>
+
<p>This release comes about two months after 1.25.0 and includes more than 70 resolved
issues, comprising a lot of new features and bug-fixes. Among others, it is worth highlighting the following.</p>
