Can I claim patent for my invention which is a little upgraded version of already patented devices. Moreover, I use same patented devices in my invention and add new functionalities to it. Is it worth patenting?
Not if it is "just" an advancement.
Improvements to processes, machines, manufactures, or compositions of matter, are patentable but only if they are new and useful, and non-obvious (among other requirements like adequate disclosure etc.)
35 USC 101-103, 112