Magento Order number Pattern

[mohit_magento]

Hi All,

I am using magento on my site. initially order number were generated like 1000000123, 1000000135 and so on. But for the last one week it id using a different pattern to generate the otder number which is based on current date. Here are few order numbers generated in lst one week:

20150623171312, 20150623171415, 20150624060656

Can anyone help me to change the order pattern as it was earlier. (1000000123, 1000000135)

Thanks,

Mohit

[Mukesh Tiwari]

Have you installed all the recommended Magento security patches?

Did you install any order management related extension?