diff --git a/doc/configuration.txt b/doc/configuration.txt
index 4a61fee95..594285ae8 100644
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -17257,14 +17257,19 @@ proto <name>
   Here are the protocols that may be used as argument to a "proto" directive on
   a bind line :
 
+   quic : mode=HTTP  side=FE|BE  mux=QUIC  flags=HTX|NO_UPG|FRAMED
     h2   : mode=HTTP  side=FE|BE  mux=H2    flags=HTX|HOL_RISK|NO_UPG
     h1   : mode=HTTP  side=FE|BE  mux=H1    flags=HTX|NO_UPG
     none : mode=TCP   side=FE|BE  mux=PASS  flags=NO_UPG
 
   Idea behind this option is to bypass the selection of the best multiplexer's
   protocol for all connections instantiated from this listening socket. For
-  instance, it is possible to force the http/2 on clear TCP by specifying "proto
-  h2" on the bind line.
+  instance, it is possible to force the http/2 on clear TCP by specifying
+  "proto h2" on the bind line.
+
+  If the ALPN or the NPN settings are configured, the specified protocols
+  should be compatible with the multiplexer's protocol to avoid any issue. For
+  instance, if "proto h1" is set, the ALPN should not be set to "h2".
 
 quic-cc-algo { cubic | newreno | bbr | nocc }[(<args,...>)]
   This is a QUIC specific setting to select the congestion control algorithm
@@ -17921,11 +17926,16 @@ check-proto <name>
     h1   : mode=HTTP  side=FE|BE  mux=H1    flags=HTX|NO_UPG
     none : mode=TCP   side=FE|BE  mux=PASS  flags=NO_UPG
     quic : mode=HTTP  side=FE|BE  mux=QUIC  flags=HTX|NO_UPG|FRAMED
+    spop : mode=SPOP  side=BE     mux=SPOP  flags=HOL_RISK|NO_UPG
 
   Idea behind this option is to bypass the selection of the best multiplexer's
   protocol for health-check connections established to this server.
   If not defined, the server one will be used, if set.
 
+  If the ALPN or the NPN settings are configured, the specified protocols
+  should be compatible with the multiplexer's protocol to avoid any issue. For
+  instance, if "proto h1" is set, the ALPN should not be set to "h2".
+
   QUIC check configuration is not fully implemented yet. First, QUIC checks may
   only be performed for QUIC servers. Second, if one or more check specific
   connection parameters is specified on a QUIC server, check protocol will
@@ -18791,10 +18801,15 @@ proto <name>
     fcgi : mode=HTTP  side=BE     mux=FCGI  flags=HTX|HOL_RISK|NO_UPG
     h1   : mode=HTTP  side=FE|BE  mux=H1    flags=HTX|NO_UPG
     none : mode=TCP   side=FE|BE  mux=PASS  flags=NO_UPG
+    spop : mode=SPOP  side=BE     mux=SPOP  flags=HOL_RISK|NO_UPG
 
   Idea behind this option is to bypass the selection of the best multiplexer's
   protocol for all connections established to this server.
 
+  If the ALPN or the NPN settings are configured, the specified protocols
+  should be compatible with the multiplexer's protocol to avoid any issue. For
+  instance, if "proto h1" is set, the ALPN should not be set to "h2".
+
   See also "ws" to use an alternative protocol for websocket streams.
 
 redir <prefix>