To update a tileset from 2.6 to 2.91.99 (will be 3.0 in the future) you must add some new graphics and update the file format strings. Currently these instructions go up to compatibility with freeciv trunk revision 32803.
The .tilespec file
- Set format of .tilespec file to options = "+Freeciv-tilespec-Devel-YYYY.MMM.DD" during development. For freeciv 3.0 options = "+Freeciv-3.0-tilespec" should be used.
- darkness_layer was merged into the new layer_order tag. If you used darkness_layer = 0, you can safely remove it. Else, see the bundled tilesets for how to use layer_order.
- minimap_intro_file (also called the 'radar graphics') is no longer supported. Simply remove minimap_entry_file entry out from the tilespec, if you have it.
- Resource now need to have extrastyle defined in the [extrastyle] section. The old hardcoded way to draw resources was equivalent of extrastyle Single1
- Optional: if you have directional unit sprites you can now set unit_default_orientation to control which one is used in worklists, help, etc -- set to "s", "nw", etc.
The .spec files
- You can add a unit icon that indicates that the unit wants the player to clarify what it should do. (The unit will pop up the action selection dialog when selected) Define it via the new unit.action_decision_want tag.