Document FirebirdSQL/jaybird#824

Author: mrotteveel

src/docs/asciidoc/appendices/systemproperties/systemproperties.adoc

@@ -52,6 +52,13 @@ This property will have no effect if `org.firebirdsql.jdbc.defaultConnectionEnco
 
 The property values are read for each connect, so the value can be changed at any time.
 
+[#systemproperties-default-enable-protocol]
+=== Default `enableProtocol` value
+
+`org.firebirdsql.jdbc.defaultEnableProtocol`::
+Configures the default value for the `enableProtocol` connection property.
+See <<ref-enable-protocol>> for more information.
+
 [[systemproperties-wire-buffers]]
 === Wire protocol buffer sizes
 

src/docs/asciidoc/reference/connection/enableprotocol.adoc

@@ -20,6 +20,11 @@ However, we recommend using the unmasked version (e.g. `"12"` for protocol versi
 * `"*"` -- enable all available protocol versions
 * `null` or empty string (`++""++`) -- default behaviour, only use supported protocols
 
+A different default value of `enableProtocol` can be set using the system property <<systemproperties-default-enable-protocol,`org.firebirdsql.jdbc.defaultEnableProtocol`>>.
+This system property is checked each time a connection configuration is created, so it can be changed at runtime.
+If you use a Jaybird `DataSource` implementation, it uses the value at the time the `DataSource` is created;
+if you use `DriverManager` -- this can include third-party data sources, it uses the value at the time the connection is created.
+
 [WARNING]
 ====
 Given these protocol versions and their Firebird version are not supported, there is no guarantee that the driver will function correctly when an unsupported protocol is enabled this way.