diff --git a/download.html b/download.html
index 3c83db07424b190e6fe48f6a93fb0a0f691b7fe7_ZG93bmxvYWQuaHRtbA==..df99ee33a75f21c3ed3128d68396d37e1f3324e6_ZG93bmxvYWQuaHRtbA== 100644
--- a/download.html
+++ b/download.html
@@ -147,7 +147,8 @@
 <ul>
 <li><p class="first">It is recommended to use PyPy to do translations, instead of using CPython,
 because it is twice as fast.  You should just start by downloading an
-official release of PyPy (with the JIT).</p>
+official release of PyPy (with the JIT).  If you really have to use CPython
+then note that we are talking about CPython 2.5-2.7 here, not CPython 3.x.</p>
 </li>
 <li><p class="first">If RAM usage is a problem, then you can (for now) tweak some parameters
 via environment variables and command-line options.  The following command
diff --git a/source/download.txt b/source/download.txt
index 3c83db07424b190e6fe48f6a93fb0a0f691b7fe7_c291cmNlL2Rvd25sb2FkLnR4dA==..df99ee33a75f21c3ed3128d68396d37e1f3324e6_c291cmNlL2Rvd25sb2FkLnR4dA== 100644
--- a/source/download.txt
+++ b/source/download.txt
@@ -138,7 +138,8 @@
 
 * It is recommended to use PyPy to do translations, instead of using CPython,
   because it is twice as fast.  You should just start by downloading an
-  official release of PyPy (with the JIT).
+  official release of PyPy (with the JIT).  If you really have to use CPython
+  then note that we are talking about CPython 2.5-2.7 here, not CPython 3.x.
 
 * If RAM usage is a problem, then you can (for now) tweak some parameters
   via environment variables and command-line options.  The following command