Index: openacs-4/packages/acs-tcl/tcl/00-icanuse-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/acs-tcl/tcl/Attic/00-icanuse-procs.tcl,v
diff -u -N -r1.1.2.39 -r1.1.2.40
--- openacs-4/packages/acs-tcl/tcl/00-icanuse-procs.tcl	28 Jan 2022 22:44:17 -0000	1.1.2.39
+++ openacs-4/packages/acs-tcl/tcl/00-icanuse-procs.tcl	23 May 2022 22:01:32 -0000	1.1.2.40
@@ -118,6 +118,7 @@
 ::acs::register_icanuse "ns_reflow_text -offset"    [acs::cmd_error_contains {ns_reflow_text} -offset]
 ::acs::register_icanuse "nsf::config profile"       [expr {[info exists ::nsf::config(profile)] ? $::nsf::config(profile) : 0}]
 ::acs::register_icanuse "ns_strcoll"                {[info commands ::ns_strcoll] ne ""}
+::acs::register_icanuse "ns_deletecookie -samesite" [acs::cmd_error_contains {ns_deletecookie ""} -samesite]
 
 #
 # At the time "ns_trim -prefix was introduced, a memory leak in
Index: openacs-4/packages/acs-tcl/tcl/utilities-procs-aolserver.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/acs-tcl/tcl/utilities-procs-aolserver.tcl,v
diff -u -N -r1.6.2.4 -r1.6.2.5
--- openacs-4/packages/acs-tcl/tcl/utilities-procs-aolserver.tcl	2 Aug 2021 21:26:55 -0000	1.6.2.4
+++ openacs-4/packages/acs-tcl/tcl/utilities-procs-aolserver.tcl	23 May 2022 22:01:33 -0000	1.6.2.5
@@ -65,6 +65,7 @@
     {-secure f}
     {-domain ""}
     {-path "/"}
+    {-samesite lax}
     name
 } {
     Un-sets a cookie.
@@ -74,7 +75,7 @@
 } {
     ad_set_cookie -replace t -expire t -max_age 0 \
         -secure $secure -domain $domain -path $path \
-        $name ""
+        -samesite $samesite $name ""
 }
 
 #
Index: openacs-4/packages/acs-tcl/tcl/utilities-procs-naviserver.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/acs-tcl/tcl/utilities-procs-naviserver.tcl,v
diff -u -N -r1.4.2.7 -r1.4.2.8
--- openacs-4/packages/acs-tcl/tcl/utilities-procs-naviserver.tcl	21 Sep 2020 11:28:56 -0000	1.4.2.7
+++ openacs-4/packages/acs-tcl/tcl/utilities-procs-naviserver.tcl	23 May 2022 22:01:33 -0000	1.4.2.8
@@ -68,14 +68,19 @@
     {-secure f}
     {-domain ""}
     {-path "/"}
+    {-samesite lax}
     name
 } {
     Un-sets a cookie.
 
     @see ad_get_cookie
     @see ad_set_cookie
 } {
-    ns_deletecookie -domain $domain -path $path -replace t -secure $secure -- $name
+    if {[::acs::icanuse "ns_deletecookie -samesite"]} {
+        ns_deletecookie -domain $domain -path $path -replace t -secure $secure -samesite $samesite -- $name
+    } else {
+        ns_deletecookie -domain $domain -path $path -replace t -secure $secure -- $name
+    }
 }
 
 #