WLC 7.5 introduced lots of new features  and you can see the full feature list from WLC Release Notes. From my network environment perspective there are few key features that I would like to have,

1. 802.11ac module support for 3600 AP (if anyone need to play with 802.11ac with Cisco wireless this is the code you should have in your 5508)

2. New Mobility – CAPWAP for Inter-controller mobility instead of EoIP (All Next Gen WLC – 3850,5760 only support CAPWAP, so if you want to have mix of old gen & new gen WLCs with mobility you have to have this enabled). I have 1×5760 & around 50×3850 switches in my access layer. One day I want to use them as WLCs.

3. mDNS enhancements

Even though I like to have these, there are certain points you need to consider before this upgrade.

1. You have to upgrade Prime Infrastructure to 1.4 & MSE to 7.5 to be fully compatible with WLC 7.5.x (PI 1.4 is not a successor release to 1.3, it is an parallel track to 1.3 to support WLC 7.5 code. Next upgrade to 1.3 would be 2.0 where as 1.4 would be upgrade to 2.1 code. It is all confusing & refer this Cisco support forum post for some clarity). There is no downgrade option from 1.4 to 1.3

2. Even with Prime 1.4 you cannot manage next gen WLCs (3850,5760).

3. There are large number of un-resolved bugs (which Cisco known about) listed in the release notes. As always there may be lots of unknown bugs since this code is just released. We went ahead with 7.4.x as they released & found out few bugs which hurts us during last 6-8 months(refer this for more detail) So we do not want to go through a similar pain with 7.5.x unless benefits outweigh drawbacks.

Therefore it is too early & risky for me to go upgrade all my 5508 (x9 of them servicing ~12k concurrent devices) running to this release. But I cannot resist it too long. There was a request from a VIP to have the capability of printing to his home printer while he is connected to corporate SSID at home using OEAP602 series AP. Yes it is a feature called “Split Tunneling” only supported in WLC 7.5.x onwards for 600 series AP. This is the WLC release note says about this

You can configure split tunneling for the Cisco OEAP to enable or disable local printer access. You can enable or disable split tunneling on a per WLAN or per remote LAN basis, or you can enable or disable split tunneling globally on the Cisco OEAP themselves.

Therefore I will be upgrading my DMZ (only that one for the time being) 5508 to shortly to enable this feature for Office Extend Home users. I will not enable “New Mobility” feature, since that will break my guest tunneling without upgrading all other controllers. I hope still I can manage this via PI 1.3 (which is the current prime version) once upgraded to (Even Cisco document says in is not compatible).

Once I read the release notes I found few other cool features as well. Here are they,

1. Output filtering using grep command
You can now use the grep command to print only the lines that match a pattern. This is especially useful when the output of certain show commands is lengthy and you have to scroll multiple times to get to the information that you need. Here are few examples

(WLC) >grep include 'Up Time' 'show sysinfo' 
Press yes to continue(y)y
System Up Time........................0 days 0 hrs 48 mins 35 secs
There are 1 lines matching the pattern Up Time 

(WLC) >grep include 'Split' 'show wlan 2'
Press yes to continue(y)y
Split Tunnel (Printers).......................... Enabled
There are 1 lines matching the pattern Split

2. Client deauthentication by username, IP Adderess instead of MAC address.
You can now deauthenticate a client by specifying the username or the IP address of the client. In the earlier releases, you could do this by specifying only the MAC address of the client. This enhancement allows multiple client sessions with the same username to be deauthenticated

config client deauthenticate {mac-addr | ipv4-addr | ipv6-addr | user-name}

3. Ping from a dynamic interface of your choice. Like source interface in extended ping command in normal IOS devices.
It is now possible to choose the interface name from which you ping:Ping from an interface of your choice by entering this command:

ping ip-addr interface-name

I will do a separate post on this Split Tunneling feature of WLC 7.5.x & how it works once I test it.

Update@ Feb 2014
Cisco has deferred this release & no longer supported or able to download. If you are running this code then it is advisable to upgrade to another code (or downgrade to unless you require some latest feature or hardware support like 3700)