Index: openacs-4/packages/acs-bootstrap-installer/tcl/20-db-bootstrap-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/acs-bootstrap-installer/tcl/20-db-bootstrap-procs.tcl,v
diff -u -r1.14 -r1.15
--- openacs-4/packages/acs-bootstrap-installer/tcl/20-db-bootstrap-procs.tcl	4 Jul 2018 17:41:02 -0000	1.14
+++ openacs-4/packages/acs-bootstrap-installer/tcl/20-db-bootstrap-procs.tcl	7 Jul 2018 10:11:27 -0000	1.15
@@ -17,6 +17,11 @@
     if { $dbn eq "" } {
         set dbn $::acs::default_database
     }
+    # When updating from versions before 5.10.0d4, namespace variable
+    # might not be initialized. Get values from conf in this case.
+    if {![info exists ::acs::db_pools($dbn)]} {
+        db_bootstrap_set_db_type errors
+    }
     return $::acs::db_pools($dbn)
 }
 
@@ -113,6 +118,9 @@
     set config_path "ns/server/$server_name/acs/database"
     set all_pools [ns_db pools]
 
+    # unset namespaced array of database pools
+    array unset -nocomplain ::acs::db_pools
+
     set database_names [ns_config $config_path {database_names}]
 
     if { [llength $database_names] <= 0 } {