Telling a version problem apart

Missing blocks, wrong colours, a world that will not open and a build that looks subtly off are four different symptoms with one cause behind them more often than not. Recognising it saves an afternoon of chasing the wrong fix.

• Gaps where specific block types should be, while everything else is intact — you are on a version older than the build.
• The world refuses to open with an error naming a version or a data format — same cause, further along.
• Blocks are present but behave oddly: stairs facing wrong, walls not connecting, slabs merged — the block data was converted between formats and lost detail.
• Everything is right but the greenery is the wrong colour — that is biome tinting, not a version problem. See the article on dead plants.
• The build looks correct in singleplayer and broken on the server — the two are running different versions.

1. 1Read the versions listed on the map's page, in the specs column beside the description. That is what the build was made for.
2. 2Check what you are actually running — the launcher for singleplayer, the console output for a server. People are often not on the version they think.
3. 3Open the map on a matching version before changing anything else. If the symptom disappears, you have your answer.
4. 4Copy the world folder before opening it on a newer version, if you might want the old one back. The upgrade happens on first load and cannot be undone.