Index: openacs-4/packages/xotcl-core/tcl/01-debug-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/xotcl-core/tcl/01-debug-procs.tcl,v
diff -u -r1.65 -r1.66
--- openacs-4/packages/xotcl-core/tcl/01-debug-procs.tcl	1 Nov 2012 23:06:56 -0000	1.65
+++ openacs-4/packages/xotcl-core/tcl/01-debug-procs.tcl	2 Nov 2012 11:42:15 -0000	1.66
@@ -1,6 +1,13 @@
 ## tell serializer to export methods, although these are methods of 
 # ::xotcl::Object
 
+if {$::tcl_version < 8.5
+    || ([regexp {8[.]5[.]([0-9]+)$} $::tcl_patchLevel _ minor] && $minor < 4)
+} {
+    ns_log error "We require for this version of xotcl-core at least Tcl 8.5.4 (avail: Tcl $::tcl_patchLevel)"
+    return
+}
+
 package require xotcl::serializer
 
 ::Serializer exportMethods {
Index: openacs-4/packages/xotcl-core/tcl/test/xotcl-avail-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/xotcl-core/tcl/test/xotcl-avail-procs.tcl,v
diff -u -r1.4 -r1.5
--- openacs-4/packages/xotcl-core/tcl/test/xotcl-avail-procs.tcl	12 Sep 2008 10:06:49 -0000	1.4
+++ openacs-4/packages/xotcl-core/tcl/test/xotcl-avail-procs.tcl	2 Nov 2012 11:42:15 -0000	1.5
@@ -19,6 +19,12 @@
 
   ? {expr {$::xotcl::version < 1.5}} 0 "XOTcl Version $::xotcl::version >= 1.5"
 
+  ? {expr {$::tcl_version < 8.5}} 0 "Tcl Version $::tcl_version >= 8.5.4"
+    if {[regexp {8[.]5[.]([0-9]+)$} $::tcl_patchLevel _ minor]} {
+      ? {expr {$minor < 4}} 0 "Tcl Version $::tcl_patchLevel >= 8.5.4"
+    }
+  }
+
   set ns_cache_version_old [catch {ns_cache names util_memoize xxx}]
   if {$ns_cache_version_old} {
     ? {set x old} new "upgrade ns_cache: cvs -z3 -d:pserver:anonymous@aolserver.cvs.sourceforge.net:/cvsroot/aolserver co nscache"