the factory must grow.
more iron for the iron gods.
*beep beep*

how to fix an old save that won't import in to a new major version or heavily modded version of Factorio:

1. back up your save to somewhere outside the save directory so you don't confuse yourself.
2. open the save in the latest version that it still runs in, and dump your inventory in to some chests near world spawn. research changes can remove entities with inventories, so check the patch/mod notes and maybe dump those inventories, too.
3. next, open your save in the map editor (/editor at the console), and convert it to a scenario.
4. then open the scenario and copy any missing or outdated assets such as locales, scripts, or artwork from the data/base/scenarios/sandbox/ directory in the game folder. you may need to overwrite & update old files in your scenario. if importing to a modded game, use the files from a new factory's savegame instead of the base game's assets.
5. after much faffing about, you should now be able to start a new game using the scenario you converted from your save. because you are starting a new game, incredibly important things like your playtime and any chat history will be reset, so keep your backups and screenshots around! stuff like research will stay because that's per force not player. cheevos will be disabled because this isn't an official scenario, but if your factory is old enough to have inspired some of them like mine has, that's not even a sacrifice.
6. in my experience, stuff won't break when doing this. also in my experience, you won't have to do this very often with vanilla factorio. wube makes damn good software and they never break saves. but things happen and this method has kept my factory around since version 0.9.0 when oil was added. that save has seven different kinds of worldgen going on Nauvis, you can bet imma keep it around.
7. disclaimer: real-time belt throughput may very, flying robot frames not included, see forum for details.