diff --git a/DOCUMENTATION.md b/DOCUMENTATION.md
index 84b3a0cf..c2e586ef 100644
--- a/DOCUMENTATION.md
+++ b/DOCUMENTATION.md
@@ -824,7 +824,10 @@ Available backends:
 : Use a Dovecot server to authenticate users.
 
 `imap`
-: Use a IMAP server to authenticate users.
+: Use an IMAP server to authenticate users.
+
+`oauth2`
+: Use an OAuth2 server to authenticate users.
 
 Default: `none`
 
@@ -1019,6 +1022,12 @@ Secure the IMAP connection: tls | starttls | none
 
 Default: `tls`
 
+##### oauth2_token_endpoint
+
+OAuth2 token endpoint URL
+
+Default:
+
 ##### lc_username
 
 Сonvert username to lowercase, must be true for case-insensitive auth