[PsychoTechFreak]

You can take a look into facility.txt under the folder "data". At the beginning of this file you find the families listed. It is only possible to upgrade an old Version of a facility with a newer Version of the same family:

Example: Build a minor city and (later on if you have researched metropolis or megalopolis) upgrade it to a better Version.

Facility Family:
A unique identifier for all facilities of the same family.
1 - Mineral Mine
2 - Organics Farm
6 - Intel Centers
7 - Distribution Centers
11 - Rads extraction
41 - Massive Planetary Shield Generators
51 - Solar Generator
52 - Crystal restructuring plant
53 - Energy Transmission Lens
54 - Cultural Centers
59 - Solar Power Plant
61 - City through Megalopolis
62 - Arcology
70 - Cities including Space Ports and Resupply Depots
160 - Settlement/Community (Rock)
161 - Settlement/Community (Ice)
162 - Settlement/Community (Gas)
170 - Agrarian Settlement through Ecosystem
171 - Agrarian Cultural Center
202 - Organics Generation
341 - Planetary Shield Generators (non-massive)
342 - Phased Planetary Shield Generators (non-massive)