How to update a tileset from 2.3 to 2.4

To update a tileset from 2.3 to 2.4 you must add some new graphics and update the file format strings.
==The .tilespec file==
* Set tilespec format of every file to options = "+Freeciv-2.4-tilespec" should be used.
===General===
* The definition of the player colors in the file colors.tilespec is merge with the data in colors.spec / colors.png and saved in game.ruleset. See also How to update a ruleset from 2.3 to 2.4.
===Features===
* You need to set tilelabel_offset_y in section [tilespec]. This is offset for map labels that one can add to scenarios in editor
==The .spec files==
* Set spec format format of every file to options = "+Freeciv-2.3-spec" should be used. (It really is 2.3, as specfile format has not changed since freeciv 2.3)
===General===
* The definition of the city images uses a simple, increasing number which is selected via an effect (City_Image). Thus, city.*_0, city.*_8, city.*_12 ... should be changed to city.*_0, city.*_1, city.*_2 ... (The relationship between city size, and possibly other properties, and these images is now defined by rulesets; see How to update a ruleset from 2.3 to 2.4)
* The file colors.spec is removed. The colors are defined in the terrain.ruleset file (terrain colors) or in game.ruleset (player colors). See also How to update a ruleset from 2.3 to 2.4.
==Various tiles==
==New files in misc/==
Category:Editing tilesets