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We’re pleased to announce that we’ve upgraded our LaTeX compile servers to make TeX Live 2020 live and available on Overleaf! As of October 2020, all new Overleaf projects will be based on TeX Live 2020 - you can read below for the key information and important changes.

What is TeX Live?

TeX Live is a free distribution of the TeX typesetting system that includes many TeX-related programs, fonts and macros packages, including LaTeX. At Overleaf we use TeX Live on our compile servers to power the real time preview and produce your project's PDF output.

Will my existing projects work as usual?

Absolutely! This upgrade to TeX Live 2020 will not affect any existing projects you are working on. All existing projects will continue to use the TeX Live image they were created with, and should continue to work as normal.

How can I switch to TeX Live 2020 for existing projects?

This is super easy with our Switch your TeX Live Compiler feature that we launched in April 2020. The TeX Live Compiler feature allows you to switch between TeX Live versions as and when you need to, and most importantly enables you to submit your work to publishers, preprint servers, and other platforms that use a specific TeX Live version to compile submissions.

What’s New in TeX Live 2020?

You can find the official release notes for TeX Live 2020 on the TUG website. The key highlights are:

• The \input primitive in all TeX engines, including tex, now accepts a group-delimited filename argument, as a system-dependent extension. It is worth being aware that “This does not currently affect LaTeX’s \input command, as that is a macro redefinition of the standard \input primitive” as noted by Norbert Preining in this blog post.
• Anyone needing to typeset complex-script languages can now use the HarfBuzz text shaping engine via two new TeX engines: LuaHBTeX and LuaJITHBTeX, derived by integrating HarfBuzz with LuaTeX and LuaJITTeX respectively. The LuaTeX engine, without HarfBuzz, is also available but LuaLaTeX now uses the LuaHBTeX engine. This means you no longer need to use a custom latexmkrc to typeset colour emojis in your Overleaf project with LuaLaTeX!
• Advanced users wishing to typeset text in Japanese may be interested to read about new primitives available in epTeX, upTeX, eupTeX.

We’ve also upgraded the underlying operating system to Ubuntu 20.04, this along with TeX Live 2020 enables new fonts for your Overleaf projects (for a full list of supported fonts see our help file Which OTF or TTF fonts are supported via fontspec?).

Key Changes in TeX Live 2020?

scrpage2

If you have been using the scrpage2 package for styling your page styles (headers and footers), this package is no longer available. The good news is that you can switch to \usepackage{scrlayer-scrpage} as a drop-in replacement.

tkz-euclide

If you have been using tkz-euclide to draw geometric diagrams: \usetikzobj{all} will now cause an error, as it refers to tkz-obj-angles.tex but this file is no longer available. According to the tkz-euclide package documentation, \usetkzobj{all} is unnecessary now, so you can remove this line from your code. (If your compiled diagram is now different from how it was rendered in TeX Live 2019, please refer to the package documentation to check for updates to the various commands.)

tkz-linknodes, tkz-graph, tkz-berge

These packages are marked obsolete on CTAN, so are not included in TeX Live 2020. If you wish to continue using these packages in your project, you will need to upload tkz-linknodes.sty, tkz-graph.sty and tkz-berge.sty, as well as any other required files, to your project.

caption and bicaption package

Starting with v3.4h of the caption package, options cannot be used anymore prior to definition. This may affect some packages and templates. For example, some thesis templates that use the bicaption package to provide bilingual captions, may need to ensure that custom caption options and styles are defined before any \captionsetup calls that make use of them.

acro package

The acro package has had a major overhaul: \DeclareAcroListStyle has been removed. If you had defined a custom list style for your acronym list using this package, it's highly likely that you'll now have to re-implement your style using new mechanisms: see the acro package documentation for details.

amssymb, amsfonts, newtxmath

The newtxmath package defines many mathematical symbols, so you should not need to load amssymb or amsfonts, if you already have a \usepackage{newtxmath} in your project, or if you're using a document class/style that loads this template. Loading amssymb and amsfonts along with newtxmath may now result in compile errors or incorrect glyphs in the output PDF.

xeCJK and ctex package bundle

The xeCJK package and ctex package bundle are frequently used for typesetting CJK documents; and specifically Chinese in the case of ctex.

The ctex package, as well as ctexart, ctexbook, ctexrep, ctexbeamer document classes no longer load the ulem and xeCJKfntef packages automatically, so you will need to load these package yourself if you need the following commands and environments:

• CJKfilltwosides, \CJKunderline, \CJKunderdot: load xeCJKfntef
• \uline: load ulem

The loading order of some packages like amsmath, newtxmath, amssymb, ctex* is now quite important; these packages are frequently used in many thesis templates. If you encounter an error with a thesis templates that had worked just fine in TeX Live 2019, but are now having compile errors in TeX Live 2020, we recommend checking with the template's authors to see if they have addressed these issues in an updated version, and that you are using the latest version of the template.

gbt7714

The method for loading the gbt7714 bibliography styles has now changed: instead of passing the "numbers" or "authoryear" option to the gbt7714 package, you should now issue a specific \bibliographystyle command. For example: \bibliographystyle{gbt7714-numerical} or \bibliographystyle{gbt7714-author-year}.

supertabular

Make sure your last row in a supertabular ends with \\!

Where can I find information on previous TeX Live versions?

Full TeX Live release notes for all versions can be found on the TUG website. We’ve also written helpful updates for previous releases including TeX Live 2019, TeX Live 2018 and TeX Live 2016.

Getting Help

As always, if you need help at any time with your Overleaf project, then please reach out to our support team, providing the link to your project, and they’ll try to help!