diff --git a/installing/upgrade/upgrade-to-r4.0.md b/installing/upgrade/upgrade-to-r4.0.md
index 21a90c3c..003c2091 100644
--- a/installing/upgrade/upgrade-to-r4.0.md
+++ b/installing/upgrade/upgrade-to-r4.0.md
@@ -90,6 +90,23 @@ Restore from your backup
    For the TemplateVM OS versions supported in R4.0, see [Supported Versions](/doc/supported-versions/#templatevms).
    If the restore tool complains about missing templates, you can select the option to restore the AppVMs anyway, then change them afterward to use one of the default R4.0 templates.
 
+Note about additional disp-* qubes created during restore
+---------------------------------------------------------
+
+One of differences between R3.2 and R4.0 is the handling of DisposableVMs.
+In R3.2, a DisposableVM inherited its network settings (NetVM and firewall rules) from the calling qube.
+In R4.0, this is no longer the case.
+Instead, in R4.0 it's possible to create multiple DVM Templates and choose which one should be used by each qube.
+It's even possible to use different DVM Templates for different operations from the same qube.
+This allows much more flexibility, since it allows you to differentiate not only network settings, but all of a qube's properties (including its template, memory settings, etc.).
+
+Restoring a backup from R3.2 preserves the old behavior by creating separate DVM Template for each network-providing qube (and also `disp-no-netvm` for network-isolated qubes).
+Then, each restored qube is configured to use the appropriate DVM Template according to its `netvm` or `dispvm_netvm` property from R3.2.
+This way, DisposableVMs started on R4.0 by qubes restored from a R3.2 backup have the same NetVM settings as they had on R3.2.
+
+If you find this behavior undesirable and want to configure it differently, you can remove those `disp-*` DVM Templates.
+But, to do so, you must first make sure they are not set as the value for the `default_dispvm` property on any other qube.
+Both Qubes Manager and the `qvm-remove` tool will show you where a DVM Template is being used, so you can go there and change the setting.
 
 Upgrade all Template and Standalone VM(s)
 -----------------------------------------