All my life I have been changing places of residence because my father got posted every 2 or 3 years to a different city or town as per the Defence force policy, whatever that be. I have made new friends, met some old ones in a different and new place few years later and visited many places in India. Among other troubles in changing places every few years is meeting old friends in a new place few years later. The friendship in 2nd standard can't be reprise in 5th standard or 8th standard with the same essence and feelings. Things change, people change and so does other things in life and in society. Meeting an old friend and deciding to do some catching up can be a bit awkward sometimes, but could be fun in some other cases. It depends on the kind of friendship and the changes that each friend has undergone. Some people even avoid the "catching up" part just to prevent the awkwardness that they may experience.
As my personal experience, now a days I am not or will not be as comfortable with some of my old friends, as I was some 5 or 6 years ago. I or he/she might expect some things from those bygone days from the other person but it may not happen. While with some other friends, the essence of those old days is still there and the friendship with same flavor is reprise with few new flavors added.
Few of my school acquaintances with whom I hardly talked while with them in school, became my good friends after we met few years later at some other place. Its strange but if I had stayed in the previous place for few more years, then that person and I wouldn't have become friends at all.
P.S. I observed something interesting in my life that I met an old friend from a school before my previous school every year since my 6th class, i.e., my stay in Bhopal till 12th class, i.e., my stay in Jalandhar.