Index: en_US.ISO8859-1/articles/committers-guide/article.xml
===================================================================
--- en_US.ISO8859-1/articles/committers-guide/article.xml
+++ en_US.ISO8859-1/articles/committers-guide/article.xml
@@ -3912,7 +3912,7 @@
 	(features which are inherently architecture-specific, such as
 	support for hardware device drivers, may be exempt from this
 	requirement).  In general, all Tier 1 platforms must have
-	build and Tinderbox support either in the FreeBSD.org cluster,
+	build and tinderbox support either in the FreeBSD.org cluster,
 	or be easily available for all developers.  Embedded platforms
 	may substitute an emulator available in the &os; cluster
 	for actual hardware.</para>
@@ -3946,6 +3946,12 @@
 	documents.  All relevant integration documentation must also
 	be integrated into the tree, or readily available.</para>
 
+      <para>Tier 1 architectures should avoid ABI changes in userland
+        libraries, system calls or supported kernel interfaces within
+        a stable branch.  Compatability shims that support the
+        existing ABI can be used as a tool to introduce ABI
+        changes.</para>
+	
       <para>Current Tier 1 platforms are &arch.i386; and
 	&arch.amd64;.</para>
     </sect2>
@@ -4002,7 +4008,8 @@
 
       <para>Current Tier 2 platforms are &arch.arm;, &arch.arm64;,
 	&arch.ia64; (through &os; 10),
-	&arch.pc98;, &arch.powerpc;, and &arch.sparc64;.</para>
+	&arch.pc98; (through &os; 11),
+        &arch.powerpc;, and &arch.sparc64;.</para>
     </sect2>
 
     <sect2>
@@ -4044,8 +4051,9 @@
 	project.</para>
 
       <para>All systems not otherwise classified into a support tier
-	are Tier 4 systems.  The &arch.ia64; platform is transitioning
-	to Tier 4 status in &os; 11.</para>
+        are Tier 4 systems.  The &arch.ia64; platform is transitioning
+        to Tier 4 status in &os; 11.  The &arch.pc98; platform is
+        transitioning to Tier 4 status in &os; 12.</para>
     </sect2>
 
     <sect2>