doc/go1.15.html | 10 ++++++++++

diff --git a/doc/go1.15.html b/doc/go1.15.html
index b9c63e2f0db6f5791c1f75ae0333c7d0d32097b8..0cbc9be60d659e4f81d2ad42edb90cc701207d89 100644
--- a/doc/go1.15.html
+++ b/doc/go1.15.html
@@ -94,6 +94,16 @@   <code>GOARCH=riscv64</code>). It also now supports asynchronous
   preemption.
 </p>
 
+<h3 id="386">386</h3>
+
+<p><!-- golang.org/issue/40255 -->
+  Go 1.15 is the last release to support x87-only floating-point
+  hardware (<code>GO386=387</code>). Future releases will require at
+  least SSE2 support on 386, raising Go's
+  minimum <code>GOARCH=386</code> requirement to the Intel Pentium 4
+  (released in 2000) or AMD Opteron/Athlon 64 (released in 2003).
+</p>
+
 <h2 id="tools">Tools</h2>
 
 <h3 id="go-command">Go command</h3>