Add docs on upgrading from a very old version (#16951)

Co-authored-by: Andrew Morgan <1342360+anoadragon453@users.noreply.github.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/docs/usage/administration/admin_faq.md b/docs/usage/administration/admin_faq.md

index 5c9ee7d0aa..092dcc1c84 100644
--- a/docs/usage/administration/admin_faq.md
+++ b/docs/usage/administration/admin_faq.md
@@ -120,6 +120,11 @@ for file in $source_directory/*; do
 done
 ```
 
+How do I upgrade from a very old version of Synapse to the latest?
+---
+See [this](../../upgrade.html#upgrading-from-a-very-old-version) section in the
+upgrade docs.
+
 Manually resetting passwords
 ---
 Users can reset their password through their client. Alternatively, a server admin