I'm having this same exact issue

oh btw I can access the admin area but that's all

Guys, you need to update all your plugins after platform update. 

Not only admin's area. you can access all other pages than dashboard and profile. 

What i have noticed, if you remove news_feed box from dashboard and profile via admin page, you could also access these pages...

After update 1.3 at local web-server admin panel working fine but site getting this error "Error 500
Internal Server Error. "

ok cool figured it out update the newsfeed plugin and make sure to go to admin after you upload the updated plugins and click the update button

Yes, you can update plugin manually or wait for an auto update request in your admin panel. Please, read release post carefully. You should update platform, plugins and themes. IN other way, you can get 500 error in some cases. 

Thanks, After update the newsfeed plugin everything is working fine.

Just for the sake of formality,

How do you update a plugin and theme?

@Mike, :-)

@Mike simply download the plugin or theme and upload it to your server and extract it as you did the first time you installed the plugin or theme

side note:I had issues with the group plugin causing a 500 error again if you guys get this issue let me know Ill post how I got that plugin to install correctly

OK,

I am sorry for being thick, I can do that without losing my setup? I mean, I have 10 groups, so I download the plugin group, install it again and it works?

I did that, and it gives me below error and I lost access to all incl. admin
Error 500
Internal Server Error,

@Joseph... please do tell!

OK my fix for GROUPS error

SSH into the server, move ow_plugins\groups to a new name, go to ADMIN area, it shows UPDATE GROUPS , rename back the groups folder, press update, now that one works...

wow..

@Mike I upload plugin through admin panel got update button and this msg:
 "The source code of 'newsfeed' plugin was updated. Need to update plugin DB."

uninstall the group plugin after first try then when you get the page that asks you to update the group DB file stay on that page and go upload the plugin again then on that page click update and things will go smoothly from there 

thats about the same as uninstalling it so either way works