updated stable tag and upgrade notice

readme.txt

@@ -4,7 +4,7 @@ Donate link: http://www.itthinx.com/plugins/affiliates
 Tags: ads, AddToAny, AddThis, advertising, affiliate, affiliate marketing, affiliate plugin, affiliate tool, affiliates, contact form, contact form 7, downloads, e-commerce, Ecwid, Events Manager, Jigoshop, lead, link, marketing, money, partner, Pay per Click, PayPal, PPC, referral, referral links, referrer, sales, shopping cart, TheCartPress, track, transaction, WooCommerce, WP e-Commerce
 Requires at least: 4.0.0
 Tested up to: 4.4.1
-Stable tag: 2.14.1
+Stable tag: 2.15.0
 License: GPLv3
 
 The Affiliates system provides powerful tools to maintain an Affiliate Marketing Program.
@@ -693,5 +693,5 @@ See [Affiliates Screenshots](http://www.itthinx.com/plugins/affiliates/affiliate
 
 == Upgrade Notice ==
 
-= 2.14.1 =
-This release contains further improvements related to the affiliate registration API.
+= 2.15.0 =
+This release adds new shortcodes that allow to show referrer information and content conditionally: [referrer], [affiliates_is_referred] and [affiliates_is_not_referred].