After announcing a major update to its Windows Phone Dev Center in August, Microsoft has followed up with another series of upgrades to its developer portal, including as many as 100 new fixes and improvements and enabling developer registration in 13 additional countries.

Microsoft says most improvements are designed to “streamline the app certification process, address app update workflow issues, and improve site performance overall.”

In addition to its site upgrades, the software giant has opened app registration in 13 new countries via its Dev Center, including: Afghanistan, Albania, Andorra, Azerbaijan, Bosnia and Herzegovina, Georgia, Iraq, Kyrgyzstan, Libya, Mongolia, Montenegro, Serbia, and Timor-Leste.

That brings the total number up to 191, but developers in the 13 new markets will only be able to register an account and submit free apps to the Windows Phone Store (formerly Marketplace).

Screen Shot 2012 08 07 at 09.05.08 520x211 Microsofts Windows Phone Dev Center gets 100 improvements, app registration opens in 13 new countries

The update comes two weeks ahead of the launch of Microsoft’s new Windows Phone 8 mobile operating system, introducing a number of new features and development options for app and game makers.

In August, the company announced that as part of its Windows Phone Dev Center overhaul, it would expand the number of countries from which developers could submit apps. It also said that developers would be able get paid in three times as many regions as was possible in August.

Other registration and payout improvements included the submission of digital tax forms for paid apps, the ability to tie in pubCenter accounts to create ad-funded apps, register using PayPal (in select markets) and the ability to share details between Windows Phone and Windows 8 accounts.