Summary of important user-visible changes for version 10 (yyyy-mm-dd):
---------------------------------------------------------------------

### General improvements

- Three short form aliases have been added for long form options when starting
`octave`.
  * `-e CODE` for `--eval CODE`
  * `-g` for `--gui`
  * `-G` for `--no-gui`

- Three long form options have been introduced for clarity.
  * `--no-init-user` : Don't read user configuration files ~/.octaverc or
    .octaverc files at startup.
  * `--no-init-site` : Don't read site-wide configuration files at startup.
  * `--no-init-all` : Don't read any configuration files at startup.

- `nchoosek` algorithm is now ~2x faster and provides greater precision.

- `nextpow2` algorithm is now more accurate for inputs very close to a power
of 2.  The output class now matches the input class for Matlab compatibility.
The function no longer accepts complex inputs and will emit an error for these
inputs.

- `jsonencode` now outputs integers and floating point integers without ".0"
suffix.

- `hist` now accepts N-dimensional array inputs for input `Y` which is
processed in columns as if the array was flattened to a 2-dimensional array.

### Graphical User Interface

### Graphics backend

- `polar` plots now include the center tick mark value, typically 0, in
the `'rtick'` parameter when the plot is created.  Subsequent modifications
to `'rtick'` by the function `rticks` will only include the center tick mark
value if it is specified.

- `view` correctly interprets cartesian viewpoints on main axes (bug #65641).

### Matlab compatibility

- `height` and `width` are now aliases for the `rows` and `columns` functions.

- All colormaps now default to a size of 256 colors. (The previous default
size was 64.)

- `griddata` output size more consistently matches the input interpolation
points when they are input as vectors.  When they are same-orientation vectors,
the outputs will be the same size as those vectors.  When either is a row
vector and the other is a column vector, the interpolating points are processed
through meshgrid and the output is a matrix the same size as the meshgrid.

- Enable the third output for `unique` with the `stable` sort option.

- `iqr` now provides compatible output for empty inputs.

- `cross` now produces row vector outputs when the inputs are a mix of row
and column vectors (bug #61295).

- `rat` now accepts complex inputs.

- Octave functions whose Matlab equivalents give errors when passed non-integer
values as sizes or dimensions now also give similar errors.
E.g., `cell (e, pi)` now gives an error in Octave about requiring integer
sizes for the cell array, matching Matlab behavior.
Previously, Octave's conversion from non-integers to integers was more lenient.

### Alphabetical list of new functions added in Octave 10

* `clim`
* `rticklabels`
* `tticklabels`

### Deprecated functions, properties, and operators

The following functions and properties have been deprecated in Octave 10
and will be removed from Octave 12 (or whatever version is the second
major release after 10):

- Functions

        Function               | Replacement
        -----------------------|------------------

- Core

        Function                              | Replacement
        --------------------------------------|------------------
        symbol_record_rep::mark_as_variable   | symbol_record_rep::mark_variable
        symbol_record_rep::unmark_as_variable | symbol_record_rep::unmark_variable
        symbol_record::mark_as_variable       | symbol_record::mark_variable
        symbol_record::unmark_as_variable     | symbol_record::unmark_variable
        interpreter::verbose                  | interpreter::init_trace
        cmdline_options::verbose              | cmdline_options::init_trace

  - A new method `rwdata ()` provides direct read/write access (a pointer) to the
data in a liboctave `Array` object (or its derived classes such as `Matrix`).
Historically, the method `fortran_vec ()` provided this access, but the name
is unclear, and it is recommended to use `rwdata ()` in any new code.  There
are no plans to deprecate `fortran_vec`.

  - The `--verbose`,`-V` command-line option has been deprecated.  Use
`--init-trace` to print the configuration files executed during initialization.

The following features were deprecated in Octave 8 and have been removed
from Octave 10.

- Functions

        Function               | Replacement
        -----------------------|------------------
        shift                  | circshift
        sparse_auto_mutate     | none (see below)

- `fminsearch` parameter passing:  A legacy, undocumented, and only partially
supported syntax for passing parameters to the minimized function `fcn` called
by `fminsearch` by appending them to the input argument list was partly
implemented since Octave 4.4.0.  Due to conflicts with other input methods,
the documentation of this syntax was removed in Octave 5.1.0.  The remaining
functionality has been completely removed in Octave 10.  Attempts to call
`fminsearch` with that syntax will result in an error.  The preferred method of
passing parameters to any of the minimization functions (including
`fminsearch`, `fminbnd`, and `fminunc`) is through the use of anonymous
functions.  Specific examples of this can be found in the "Minimizers" section
of the Octave manual.

### Build system

- Octave now requires a C++ compiler that is compliant with C++17 (preferably
with GNU extensions).


Summary of bugs fixed for version 10.1.0 (yyyy-mm-dd):
----------------------------------------------------

### Old release news

- [Octave 9.x](etc/NEWS.9.md)
- [Octave 8.x](etc/NEWS.8.md)
- [Octave 7.x](etc/NEWS.7.md)
- [Octave 6.x](etc/NEWS.6.md)
- [Octave 5.x](etc/NEWS.5.md)
- [Octave 4.x](etc/NEWS.4)
- [Octave 3.x](etc/NEWS.3)
- [Octave 2.x](etc/NEWS.2)
- [Octave 1.x](etc/NEWS.1)