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/**
* @page transition3_4 Transition Manual (3.x -> 4.0)
*
* There are not that major non-backwards-compatible changes between libyang version 3 and 4 and the version was
* increased in part due to new functionality. The main new feature, which most of the changes are related to, is the
* ability to __serialize (print) compiled YANG context__. What is more, such a printed context does not have to be
* deserialized to be used by applications and they can directly read the printed context in run-time. This saves time
* when reusing contexts since they do not always have to be created in every process but also potentially a lot of
* memory since all the processes on the system may share a single printed context. Naturally, such a concept has
* some limitations that are mentioned in detail in the documentation (@ref howtoPrintedContext).
*
* Related to this feature there were lots of minor changes to make sure all the intended functionality works. Most
* importantly, there are now __2 dictionaries__ for a context. One, read-only for the strings in the compiled context
* and the other for YANG data that can be written to normally. The main consequence of this is that comparing
* directly (the addresses) of strings from these 2 dictionaries will not work. Also, it is now possible to __free all
* the parsed modules__ from the context to save memory. The library functions should all be adjusted and handle such a
* situation properly. Next, all __plugin references__ were replaced by an `uintptr_t` value but there are functions
* ::lysc_get_type_plugin() and ::lysc_get_ext_plugin() for getting the actual plugin structures. Then, __default values
* are stored as strings__ in the schema nodes. To learn their real type or get their canonical value, use
* ::lyd_value_validate_dflt(). Finally, some new callbacks were required for extension-instance plugins so that they
* can be printed with the context as well.
*
* Other notable changes include major LYB binary data format optimizations. The effect in API is that wherever a size
* of a value is required, it is now expected in __bits instead of bytes__. Next, there are extension plugin API
* improvements to account for custom XPath root definitions. Then, __obsolete nodes are not compiled__ and cannot be
* instantiated in data by default but can be if requested by a context flag. Finally, the __"default" metadata instance__
* connected to the `ietf-netconf-with-defaults` YANG module is now in the proper namespace, which is not the namespace
* of this module. Other minor NBC changes should be reported by the compilator and they should be explained in the
* documentation of the corresponding changed functions.
*
* The complete generated list of changes (without any additional notes) can be found in
* <a href="../compat_report_3_4.html">the compatibility report</a>.
*
*/
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