diff --git a/docs/services/gotosocial.md b/docs/services/gotosocial.md
index 2372f40..79a9b8e 100644
--- a/docs/services/gotosocial.md
+++ b/docs/services/gotosocial.md
@@ -8,6 +8,7 @@ This service requires the following other services:
 
 - a [Postgres](postgres.md) database
 - a [Traefik](traefik.md) reverse-proxy server
+- (optional) the [exim-relay](exim-relay.md) mailer
 
 
 ## Configuration
diff --git a/docs/services/healthchecks.md b/docs/services/healthchecks.md
index a4305dc..027b99c 100644
--- a/docs/services/healthchecks.md
+++ b/docs/services/healthchecks.md
@@ -9,6 +9,7 @@ This service requires the following other services:
 
 - a [Postgres](postgres.md) database
 - a [Traefik](traefik.md) reverse-proxy server
+- (optional) the [exim-relay](exim-relay.md) mailer
 
 
 ## Configuration
diff --git a/docs/services/nextcloud.md b/docs/services/nextcloud.md
index 02429e3..1edb422 100644
--- a/docs/services/nextcloud.md
+++ b/docs/services/nextcloud.md
@@ -9,7 +9,8 @@ This service requires the following other services:
 
 - a [Postgres](postgres.md) database
 - a [Traefik](traefik.md) reverse-proxy server
-- a [Redis](redis.md) data-store (optional), installation details [below](#redis)
+- (optional) a [Redis](redis.md) data-store, installation details [below](#redis)
+- (optional) the [exim-relay](exim-relay.md) mailer
 
 
 ## Configuration
diff --git a/docs/services/vaultwarden.md b/docs/services/vaultwarden.md
index 14867a6..ba0325a 100644
--- a/docs/services/vaultwarden.md
+++ b/docs/services/vaultwarden.md
@@ -9,6 +9,7 @@ This service requires the following other services:
 
 - a [Postgres](postgres.md) database
 - a [Traefik](traefik.md) reverse-proxy server
+- (optional) the [exim-relay](exim-relay.md) mailer
 
 
 ## Configuration