updates the link to the Mastering PowerShell book (#2520)

free-programming-books.md

@@ -1776,7 +1776,7 @@ For resources on Angular, Backbone, D3, Dojo, Ember, Express, jQuery, Knockout,
 * [Ditch Excel: Making Historical & Trend Reports in PowerShell](https://www.gitbook.com/book/devopscollective/ditch-excel-making-historical-trend-reports-in-po/details) (PDF, ePub, MOBI)
 * [Introduction to PowerShell for Unix People](https://www.gitbook.com/book/devopscollective/a-unix-person-s-guide-to-powershell/details) (PDF, ePub, HTML)
 * [Layman’s Guide to PowerShell 2.0 remoting](http://www.ravichaganti.com//blog/wp-content/uploads/2010/12/A%20layman's%20guide%20to%20PowerShell%202.0%20remoting-v2.pdf) (PDF)
-* [Mastering PowerShell](http://powershell.com/cs/login.aspx?ReturnUrl=%2fcs%2fblogs%2febook%2fdefault.aspx)
+* [Mastering PowerShell v2](http://community.idera.com/powershell/powertips/b/ebookv2#pi619PostSortOrder=Ascending)
 * [PowerShell 2.0 – One CMDLET At A Time](http://www.jonathanmedd.net/wp-content/uploads/2010/09/PowerShell_2_One_Cmdlet_at_a_Time.pdf) (PDF)
 * [PowerShell Succinctly, Syncfusion](https://www.syncfusion.com/resources/techportal/ebooks/powershell) (PDF, Kindle) *(Just fill the fields with any values)*
 * [Secrets of PowerShell Remoting](https://www.gitbook.com/book/devopscollective/secrets-of-powershell-remoting/details) (PDF, ePub, MOBI)