Summary of important user-visible changes for version 11 (yyyy-mm-dd):
---------------------------------------------------------------------

### General improvements

- The internal interface to Java has been updated to be more memory-efficient
  (faster culling of unused objects).  Building Octave from source code with
  Java support now requires JDK 1.9 or newer.  Distributed, precompiled
  versions of Octave will run with any JVM.

- The `pkg` command has these user-visible changes:
  * The package installation command `pkg install foo` now automatically
    determines whether `foo` is a local file, a URL, or an unqualified package
    name in that order, and installs it as appropriate.  The `-forge` option is
    no longer required.
  * There is a new search command for packages: `pkg search foo bar baz`
    searches the Octave Packages index for packages having all the listed
    keywords in their description.  Search terms can also be specified as
    regular expressions.
  * The old command `pkg list -forge`, which returned a list of packages found
    online, has been replaced by `pkg search -refresh -all`.
  * Package metadata is now cached locally on the computer as a backup for
    reliability.  It is updated automatically when an operation that needs the
    current package index such as `install`, `update`, or `search` is run the
    first time in an Octave session.  Metadata updates can also be done on
    demand with the new option `-refresh` for those three actions.
  * Package tarballs are now verified using SHA256 if they are downloaded
    during `pkg install` or `pkg update`.

- Convolution of short and wide arrays (especially row vectors) is now faster
  by anywhere from 10% to 150X, depending on the array size and shape.
  Previously, convolution of tall and skinny arrays (especially column vectors)
  was much faster than convolving short and wide ones, requiring transposition
  or permutation of the inputs for performance.  Now Octave automatically picks
  the fastest calculation order irrespective of the input orientation.

- The functions `sum`, `cumsum`, `sumsq` now have special code for logical
  inputs resulting in performance improvements of up to 6X.

- The function `sum` now fully supports increased precision through the
  `"extra"` optional argument, which is also available for sparse arrays.

- The function `norm` now uses Kahan summation resulting in more accurate
  results (.02% for data of class `single`).

- New function `_Exit` has been added which makes it possible to use
  `fork`/`_Exit` sequence to perform work in parallel child processes for
  potential performance gains.

- The `fzero` function is now more accurate (1-2 eps when `TolX` is eps).

- The `randi` function has been completely rewritten and is now 4.5X faster
  while using some 3.5X less memory than before.

- The `roots` function now accepts only inputs of type `double` or `single`.

- The `mean` function no longer accepts character array inputs.  It does
  continue to accept logical and integer types as input.  Convert any character
  input to an accepted input type.

- All core statistics functions (other than `mean` as described above) now
  accept only inputs of type `double` or `single`.  Convert other input data
  types to `double` or `single`.

- On dot-indexing of `classdef` objects, `subsref` now tries to resolve the
  symbol name to a property first, and if a property is not found then it will
  look for a method.

### Graphical User Interface

- The File Browser now has two tabs: the first for browsing the file system as
  usual, and the second for viewing and managing all open editor files.

- The Find File dialog now offers most recently used lists for input fields and
  the ability to search for/in several file patterns at the same time.

- The GUI now uses scalable SVG icons for beautiful display at any size.

- The GUI now uses the default Octave command prompt.  This prompt is
  completely customizable by calling `PS1` in an initialization file such as
  `.octaverc`.  To recover the former behavior of the GUI use
  `PS1 ('>> '); PS2 ('')`.

- The GUI has two new user preferences: one for showing a small splash screen
  at startup, and one for using the directory of the currently focused editor
  file instead of the current Octave directory as the initial folder for the
  Open File dialog.

- The text of the Octave GUI has been translated to a new language: Asturian.
  It uses the ISO 639 language code ast_ES.

### Graphics backend

- `polar` plot background patch object has been moved to the Z=0 plane to
  permit view changes that previously resulted in an obscured plot area
  (bug #67574).

- Octave no longer strips leading and trailing spaces from user-specified
  ticklabels (bug #67302).  This makes it possible to use a monospaced font to
  align labels as the user intends.  This change is Matlab-compatible.

- The `XMinorTickValues`, `YMinorTickValues`, `ZMinorTickValues` axes
  properties that were previously hidden have been made visible to allow users
  to control the position of minor ticks (bug #67394).

- Printing to PDF format is now ~25% faster.

- Improvements to alpha blending with newer versions of OpenGL.

### Matlab compatibility

- The warning `"Octave:language-extension"` is no longer emitted for automatic
  broadcasting which Matlab has supported since version 2016B.

- Broadcasting now works on sparse matrix operations as well as mixed
  operations between sparse and full matrices.

- Broadcasting now works on diagonal matrix operations as well as mixed
  operations between diagonal matrices and vectors.

- All basic operations functions now properly handle empty inputs and return
  correctly sized output arguments for both dense arrays and sparse matrices.

- The functions `all` and `any` now accept the optional arguments `"all"` or
  `vecdim`.

- The functions `cumprod` and `cumsum` now accept the optional arguments
  `"all"` or `vecdim`, `direction`, and `nanflag`.

- The functions `min` and `max` now support the optional arguments `"all"` or
  `vecdim`, `nanflag`, and the paired argument `"ComparisonMethod"` with options
  `"real"`, `"abs"`, and `"auto"`.  The `"linear"` indexing flag is now also
  supported, when a second output argument is requested.

- The functions `cummin`, and `cummax` now support the optional arguments
  `"all"` or `vecdim`, `nanflag`, `direction`, and the paired argument
  `"ComparisonMethod"` with options `"real"`, `"abs"`, and `"auto"`.  The
  `"linear"` indexing flag is now also supported, when a second output argument
  is requested.

- The functions `prod`, `sum`, and `sumsq` now accept the optional arguments
 `"all"` or `vecdim`, `nanflag`, and `"default"` in `outtype`.  `prod` and
 `sumsq` functions now retain the class of the input argument by default.
 'sumsq' now also accepts an `outtype` argument.

- The functions `bounds`, `center`, `meansq`, `range`, `statistics`, and
  `zscore` now accept the optional arguments `"all"` or `vecdim`, and
  `nanflag`.

- The functions `kurtosis`, `mode`, `moment`, `prctile`, `quantile`, and
  `skewness` now accept the optional arguments `"all"` or `vecdim`.

- The function `mean` now accepts the optional paired argument `"Weights"`.

- The function `iqr` now calculates an optional second output `q` which
  contains the 25th and 75th quantiles used to calculate the interquartile
  range.  It also now accepts the optional arguments `"all"` or `vecdim`.

- The function `quantile` now also accepts a positive integer as the second
  input argument specifying evenly spaced cumulative probabilities.

- The functions `strncmp` and `strncmpi` now return true for `N=0` for Matlab
  compatibility.

- The function `gradient` with a numeric input now only accepts type `double`
  or `single`.

- The function `polyfit` now returns the highest powers possible and the
  constant term when there is insufficient data to create all `N` terms of the
  polynomial.  The output structure has a new field `rsquared` which is the
  coefficient of determination describing how well the polynomial fits the
  data.

- The function `cellfun` now fails if the returned type does not match in the
  invocations for each cell element.  In earlier versions, the elements were
  converted to a compatible type if possible.

- The function `speye` can now be called with zero arguments for compatibility
  with the full-matrix function `eye` and Matlab-compatibility.

- The function `containers.Map` now supports char N-D arrays as keys.

- The function `qp` now has a new input option `"AllowSemidefinite"` for
  problem instances where the Hessian matrix is positive semi-definite instead
  of positive definite.  The default value is `false`.

- The function `qr` for a dense matrix input `A` and a single output now
  returns just the matrix `R`, rather than an augmented version from LAPACK
  with additional information in the lower-triangular portion of the matrix.
  This resolves the output incompatibility with the sparse calling syntax for
  this function, as well as the incompatibility with Matlab.

- The `weboptions` function has been re-written internally.  Support for
  non-integer `Timeout` values, and the special value `Inf`, has been added.

- The `urlread` and `urlwrite` functions now make use of various `weboptions`
  such as timeouts and user credentials.  The old calling form of passing a
  cell array is still supported for backward compatibility.

- The functions `fill` and `fill3` now handle all input combinations of vector
  and matrix vertex data and color data in a Matlab-compatible way.

- The `image` function now validates that `x` and `y` inputs are vectors, and
  accepts and processes 1-element vectors for compatibility.

- The `ind2rgb` and `ind2gray` functions now clip exceptional values such as
  `NaN` or `Inf` to the last value in the colormap for compatibility.

- The function `colorbar` now requires the `location` input to be the first
  argument rather than the last argument.  This may require updating existing
  Octave scripts.  The graphics properties `AxisLocation`, `Direction`, and
  `TickLabels` have been implemented.

- The `newplot` function has been re-written to remove functionality that was
  possibly never used in Octave, and has been removed from Matlab.  The
  function is also more compatible, and does not change the current figure
  unexpectedly.  However, any user plotting code that depends on this broken
  behavior will need to be updated.

- The `uitable` property `"ColumnWidth"` now supports the argument `"fit"`
  which produces smaller column widths than `"auto"` (sized to width of data,
  rather than possibly including `ColumnName` in width calculation).
  Specifying small numeric widths down to 1-pixel now works correctly.

- The `KeyEvent` structure passed as an input paramater to graphics callback
  functions such as `KeyPressFcn` now returns fieldnames in the same order
  as Matlab: `Character`, `Modifier`, `Key`.

- The `KeyEvent` structure now includes the fields `Source` (graphics handle
  of object returning `KeyEvent`) and `EventName` (e.g., `KeyPress` or
  `KeyRelease`).

### Alphabetical list of new functions added in Octave 11

* `_Exit`
* `assert_equal`
* `corrcov`
* `dither`
* `funm`
* `mape`
* `rms`
* `rmse`
* `trexc`
* `xline`
* `yline`

### Deprecated functions, properties, and operators

The following functions and properties have been deprecated in Octave 11
and will be removed from Octave 13 (or whatever version is the second
major release after 11):

- Functions

        Function               | Replacement
        -----------------------|------------------
        polyfit output s.X     | polyfit output s.V

- Core

        Function                  | Replacement
        --------------------------|--------------------------
        octave::math::x_nint      | octave::math::round
        octave::math::isinteger   | octave::math::is_integer

    The environment variable `OCTAVE_LATEX_DEBUG_FLAG` to enable debugging of
    the latex interpreter has been renamed to `OCTAVE_LATEX_DEBUG`.

    The environment variable `QTHANDLES_DEBUG` to enable debugging of the GUI
    has been renamed to `OCTAVE_QTHANDLES_DEBUG`.

The following mapper function typedefs have been deprecated in Octave 11
and will be removed from Octave 12 (or whatever version is the first
major release after 11):

- Function typedefs

    * `b_d_Mapper`
    * `b_c_Mapper`
    * `d_d_Mapper`
    * `d_c_Mapper`
    * `c_c_Mapper`
    * `b_f_Mapper`
    * `b_fc_Mapper`
    * `f_f_Mapper`
    * `f_fc_Mapper`
    * `fc_fc_Mapper`

The following features were deprecated in Octave 9 and have been removed
from Octave 11.

- Core

        Function                                     | Replacement
        ---------------------------------------------|-----------------------------------
        octave::initialized                          | octave::is_initialized
        octave::same_file                            | octave::sys::same_file
        octave::interpreter_initialized              | octave::interpreter_is_initialized
        all_ok (Array<octave::idx_vector>&)          |
        idx_vector::bool ()                          |
        octave_value (const Array<octave_value>& a)  | octave_value (const Cell&)

  - The `octave_value (const Array<octave_value>& a)` constructor was
    deprecated in Octave 10 and was removed after only one major version.

### Old release news

- [Octave 10.x](etc/NEWS.10.md)
- [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)
