You Do Need power plug adapter while traveling from Micronesia to Serbia.

Here is Why You Need An Adapter

The outlet and plug type used in Serbia are C and F and in Micronesia are A and B. This is how they look like.

Micronesia

In Micronesia, outlets of type A and B are in use.

Type A

Type B

Serbia

In Serbia, outlets of type C and F are in use.

Type C

Type F