How to add SIBs ?

Only sib 1, 2 and 3 are available, how to support others ?

You can add whatever sib you want so that eNB will broadcast them.

Create your sib file

First, you need to create your sib file.
As specified in documentation, sib file must be written in GSER syntax.
You can find example for sib5 and sib15 to start with but you'll need 3GPP ASN.1 definition.

Add sib file to configuration

When your file has been created, you must add it in sib_sched_list array:

sib_sched_list: [ "sib2_3.asn", "sib5.asn", "sib15.asn" ]

Broadcast

Last step is to update sib1 definition to configure your sib broadcast configuration.
Take a look at sib1.asn example file at schedulingInfoList section.
You need to add an entry for each element of sib_sched_list array:

Note that you can mix several sibs in same file as done in sib2_3.asn example