Admin page just keeps refreshing after php update to 7.0

Question

I was running a magento website on my localhost, and recently ubuntu asked me to update to 16.04LTS, since it is LTS I choose to upgrade. But, Unfortunately It upgraded my PHP version to 7.0.

I am sure that is the only change after which The admin page stopped working. It does not give me any error, but just refreshes the admin login page.

I have googled a lot, but many suggest change in Varien.php, which I have never touched. And also about permissions for /var/sessions, which is also untrue in my case. And many more, but none of the scenarios as that of mine. Any help would be highly appreciated.

Answer 1

if you are not ready for php 7.0 just downgrade to php 5.6:

sudo add-apt-repository ppa:ondrej/php
sudo apt-get update
sudo apt-get install php7.0 php5.6 php5.6-mysql php-gettext php5.6-mbstring  libapache2-mod-php5.6 libapache2-mod-php7.0
sudo a2dismod php7.0 ; sudo a2enmod php5.6 ; sudo service apache2 restart

https://askubuntu.com/questions/761713/how-can-i-downgrade-from-php-7-to-php-5-6-on-ubuntu-16-04/761735

Answer 2

Today (27-Oct-2016 9:55AM Singapore Time), I tried to test Magento 1.9.2 on PHP 7.

Here my initial problems with php 7.

1. Admin Login redirect login page (solved by comment $this->renewSession(); under app/code/core/Mage/Admin/Model/Session.php or you can override this class file with magento recommended way)
2. Customer cannot create (Decoding Error in Zend_Json::decode()) function
3. Tax Calculation wrong
4. Coupon code calculation wrong
5. And a lot more unseen problems

So, I realized that all these solution are not sustainable way with php 7 and Magento 1x

My personal recommendation –

Downgrade to PHP5.6. Bad news is 1x slower than PHP 7.