* Update internals, keep the lights on.

 * Fix regression with automatic detection and selection of small cap…

…s when the font

    script or language was requested but not found. (#517)

  * Add additional tests to check against regressions. (#516, #518)

  * Improve message in log file when defining a font without small caps.

  * Demote warnings when Script or Language are requested but not found to the log file
    instead of the console. (#421)

 * Now that `Script` and `Language` are retained even if the font doe…

…sn't support them,

    we can no longer check for font feature existence before applying the OpenType tags.
    This release removes checking. (#515)

  * Fix bug/regression in loading font families constructed from fonts with different file
    extensions; e.g.: (#514)

        \setmainfont{MyLato}
          [
            UprightFont       = Lato-Regular.ttf ,
            BoldFont          = FiraSans-Bold.otf ,
          ]

 * Fix copy/paste regression bug with the `Language` feature (primari…

…ly exposed through `babel` package). (#513)

  * Re-sync with `expl3` for deprecated commands.

 * Add new `Letters=Uppercase` (LuaLaTeX only) as an interface to `lu…

…aotfload`

    feature which automatically performs case-changing at the font level
    (i.e., not using macros to process the text tokens). (#461)
  * Fix long-standing bug when loading fonts which only have extensions specified internally to the font
    shape (#504). E.g.:

        \setmainfont{pagella}[ UprightFont = texgyrepagella-regular.otf ]

  * If a font is loaded with a specific script (e.g. `Script=CJK`) and it is not
    available within the font, `fontspec` previously would fall back on a default script.
    This is now changed to always pass through the requested script so the renderer can
    make use of that information regardless of whether the font itself supports the script.
    (#507)
  * Remove LuaTeX code that resets various `hypenchar` settings seemingly erroneously. (#344)
  * Rework documentation to remove reference to local and non-free fonts. This allows
    compilation via Github Actions, which will aid streamlining/automating releases in the future. (#157, #465)
  * Adjust approach to removing spaces from font names internally. This may have unintended
    consequences, please write if so. (#484)
  * Work around clash if a class defines an option of (say) `math=foo`, where `fontspec`
    is expecting `math=true`. Now, the global option will be ignored. (#501)

 * Added a `Scale=MatchAveragecase` paramater which averages `Scale=M…

…atchLowercase` and `Scale=MatchUppercase`.

  * Switched options to LaTeX keyval handler.
  * Added option `verbose` to undo silent/quiet.
  * `euenc`/`tuenc` options are now obsolete (TU is the only encoding).
  * Support variable fonts under LuaLaTeX.
  * Skip scanning for filenames when loading fonts by name on LuaLaTeX.
  * Allow restricting filename lookup to kpathsea lookups using `KpseOnly`.
  * Added support for named colors from l3color.
  * Support with lualatex spotcolors and cmyk colors in the pdf.

 * Add `SwashFont` and `BoldSwashFont` features to support LaTeX's no…

…w-builtin `\textsw`

    and `\swshape` commands, with matching `SwashFeatures` and `BoldSwashFeatures`.
    A simple implementation that has scope to get more complex if need be.
  * Remove some legacy code that extended the NFSS in ways that are now handled by
    LaTeX2e natively.
  * Long neglected updates through various Github Issues and pull requests.
    Thanks for your patience with the delays.

 * Define both `b` and `bx` font series by default to avoid spurious …

…warnings in some

    cases, and broken behaviour in pathological cases.

 * Eroneous uses of `language=DFLT` changed to `language=dflt`.

  * Fix spurious error in some cases of `SlantedFont` and `BoldSlantedFont`
    being specified in a `.fontspec` file.
  * Fix regression with `unicode-math` related log files showing the wrong
    NFSS-based font ‘identifier’.

 * Fix regression that broke changing the default encoding after `fon…

…tspec` was loaded

    (e.g., to use legacy fonts by default but use a `fontspec` font occassionally).
  * Fix bug exhibited in `polyglossia` and perhaps elsewhere when `Script` is set without
    a corresponding `Language`.
  * Use `\familydefault` instead of `\rmdefault` when calculating scaling parameters in
    `Scale=MatchLowercase` and `Scale=MatchUppercase`.