doc: Update with mgmt-api version 1.13
diff --git a/doc/mgmt-api.txt b/doc/mgmt-api.txt
index 9384f70..2748213 100644
--- a/doc/mgmt-api.txt
+++ b/doc/mgmt-api.txt
@@ -26,7 +26,8 @@
 Linux kernel v4.1	Version 1.9
 Linux kernel v4.2	Version 1.10
 Linux kernel v4.5	Version 1.11
-Linux kernel v4.6	Version 1.12 (not yet released)
+Linux kernel v4.6	Version 1.12
+Linux kernel v4.8	Version 1.13 (not yet released)
 
 Version 1.1 introduces Set Device ID command.