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21
22There are three extensions in various versions:
23
241  version_XXX/plain.oxt has no dependencies and no license.
252a version_XXX/dependency.oxt has an unsatisfied dependency and no license.
262b version_nodependencies_XXX/dependency.oxt is identical to 2a but without the
27   dependency.
283  version_XXX/license.oxt has no dependencies and a license.
29
30The different versions are:
31
32A  version_none contains no version element (treated as version "0").
33B  version_badelement contains a bad <version val="1"/> (not allowed by the
34   specification, but treated by the current implementation as version "0").
35C  version_badvalue contains a bad <version value="1.a"/> (not allowed by the
36   specification, but treated by the current implementation as version "1").
37D  version_0.0 contains <version value="0.0"/> (same as version "0").
38E  version_1.2.3 contains <version value="1.2.3"/>.
39F  version_1.2.4.7 contains <version value="1.2.4.7"/>.
40G  version_1.02.4.7.0 contains <version value="1.02.4.7.0"/> (same as version
41   "1.2.4.7").
42H  version_1.2.15.3 contains <version value="1.2.15.3"/>.
43
44The total order among the various versions is thus
45
46  A = B = D < C < E < F = G < H.
47
48Things to watch for:
49
50- If version y of extension e is to be installed and version x < y of
51  extension e is already installed, then
52   unopkg add e
53  will replace x with y.
54
55- If version y of extension e is to be installed and version x >= y of
56  extension e is already installed, then
57   unopkg add e
58  will fail with an error message.
59
60- If version y of extension e is to be installed and any version x of
61  extension e is already installed, then
62   unopkg add -f e
63  will replace x with y.
64
65- If version y of extension e is to be installed and any version x of
66  extension e is already installed, then
67   unopkg gui "Add..."
68  and
69   soffice "Tools - Package Manager... - Add..."
70  will query with a dialog whether to replace x with y.  The dialog will have
71  "OK" (replace) preselected if x < y, and "Cancel" otherwise.
72
73- If replacing an installed version x of an extension e with a version y fails
74  because y has unsatisfied dependencies, or because y has a license to which the
75  user does not agree, version x is left installed afterwards.
76
77- Checking for already installed versions of an extension is only done within a
78  single layer (unopkg versus unopkg --shared; "My Packages" versus
79  "OpenOffice Packages" in unopkg gui/soffice), not across layers.
80