diff --git a/_posts/2015-02-24-znc160-ssl.md b/_posts/2015-02-24-znc160-ssl.md
index 94fa754..39caa32 100644
--- a/_posts/2015-02-24-znc160-ssl.md
+++ b/_posts/2015-02-24-znc160-ssl.md
@@ -90,9 +90,9 @@ function like suggested by @DarthGandalf on \#znc.*
 
 ## I am asked to verify fingerprint for network with valid certificate
 
-*Added on 2015-09-03.*
+*Added on 2015-09-03. 4. added on 2016-01-26.*
 
-There are usually three causes for this. Lets use freenode as example
+There are usually four causes for this. Lets use freenode as example
 network.
 
 1. You don't have `ca-certificates` package installed, so your system
@@ -107,6 +107,13 @@ network.
    Validating the certificates either by trusted certificates or verifying
    the fingerprints securely manually protect you from this. If MITM is the
    case, you shouldn't connect.
+4. You have `ca-certificates` installed, but the remote certificate is
+   signed by CA that is not included in it. You could try installing
+   system updates in case `ca-certificates` have been updated or you will
+   have to treat the certificate as invalid until ZNC starts supporting
+   it's own CA storage. See (and comment if you encounter this)
+   [znc/znc#909](https://github.com/znc/znc/issues/909).
+
 
 * * * * *