Compatibility of FF[4]

The following list summarizes the compatibility problems of FF[4]. This is done both ways: problems for old (FF[3]) applications when reading a FF[4] file (3 rd 4) and problems of converting FF[3] to FF[4] (3->4). 'np' is used as abbreviation of 'no problem' and 'nrp' is used as abbreviation of 'not really a problem'.

If you find some compatibility issues I've missed, please let me know.

General & Types

Verbose property names no longer exist.
- 3->4: np (delete all lowercase letters from IDs)
- 3 rd 4: np
Five property types are introduced (and thus 2 node types)
- 3->4: FF[3] files may have mixed setup and move-properties in one node. In that case an application should split that node into two nodes: all setup, root and game- info properties and the node name ('N[]') into the first node, all other properties into the second.
- 3 rd 4: np
FF[3] text type is split into two types: SimpleText and Text.
- 3->4: np
- 3 rd 4: Soft linebreaks may be treated as hard linebreaks
Within the text types anything after a '\' is inserted verbatim.
- 3->4: np
- 3 rd 4: FF[3] only knows some 'escaped' chars. It's uncertain what old applications will do (most likely their routines are already coded in the newly specified way).
Recangular boards and boards >19x19 possible
- 3->4: np
- 3 rd 4: totally incompatible
Compressed point lists
- 3->4: np
- 3 rd 4: totally incompatible
Time values are in seconds
- 3->4: concerning server-games: np, otherwise wrong time is displayed
- 3 rd 4: np
Used (default) charset defined
- 3->4: some files may contain a charset different from the default. Text will then be unreadable (unless the application allows to switch to another charset manually).
- 3 rd 4: nrp (as default charset is the one used in FF[3])
Pass move may be '[]' now (alternativ to '[tt]')
- 3->4: np
- 3 rd 4: '[]' pass may cause problems (at the least the move will be ignored)

Properties

Obsolete properties
(CH, SI, SE, LT, ID, OM, OP, CI, OV, BS, WS, SC, RG)
- 3->4: nrp (properties are treated as unkown properties and are preserved. Information is no longer displayed, though.)
- 3 rd 4: np
New properties
(AP, ST, AR, LN, SQ, OT, BO, WO, DD, VW, PM)
- 3->4: np
- 3 rd 4: nrp (properties are treated as unkown properties. Information is not displayed though. Some applications may even strip these properties without displaying a warning)
LB may hold more than 4 chars now
- 3->4: np
- 3 rd 4: only 4 chars are displayed/saved (labels get cut)
SZ may hold rectangular boards now
- 3->4: np
- 3 rd 4: incompatible
Format of DT,RE and RU is specfied explicitly
- 3->4: unknown formats may appear - should be corrected if possible
- 3 rd 4: np
FG may contain flags and diagram name
- 3->4: np
- 3 rd 4: nrp (information may get lost though)