Difference between ST18, ST18i and SO-03c

[#1]

Anyone knows the difference between these models?

My unit displays ST18i in the About Phone menu. When I was prompted of a new firmware version, I looked up SEUS which only displays ST18 and SO-03c. I selected the former since its the one nearest my phone's model. All of them are Xperia Ray.

[Martha- · Accepted solution]

Choose ST18 (the i version has call frequencies for your region).

SO-09c is the Asia equivalent.

[#3]

Thank you for clarifying Tita Martha.