• ## New Feature: Select your TeX Live Compiler Version

Posted by Dan on April 30, 2020We’re pleased to announce that we are now providing the option of selecting which TeX Live version will be used to compile your project. This enables you to work with the latest available versions of LaTeX packages, lets you adjust your projects to run with older versions as required, and helps you submit your work to publishers that use a specific TeX Live version to compile submissions. How does Overleaf decide which TeX Live version to use? How can I switch between TeX Live versions? Why would I switch TeX Live versions? What is TeX Live? What are some examples of changes between TeX Live versions? What are the TeX Live versions? How will this affect my Overleaf projects? Will this help with my arXiv submission? How does Overleaf decide which TeX Live version to use? When you create a new project (or copy an existing project), the project will, by default, be compiled using the latest version of TeX Live that we have available. When we provide a new version of TeX Live for our users, we do not automatically upgrade existing projects. Doing this automatically could cause errors or warnings within your existing projects due to differences between TeX Live versions. With this new feature, you can now select which TeX Live version will be used to compile your Overleaf project. How can I switch between TeX Live versions? To change the TeX Live version for a specific project, simply click into the left hand menu. and click on the TeX Live menu option under Settings: Why would I switch TeX Live versions? You may want a newer version of TeX Live for one of your existing projects. You can move the TeX Live version used by your project to a more recent version that provides a package, command, or language feature that you would like to use. However, before doing this we recommend that your project compiles error-free, and that you understand any remaining warnings that the compiler has provided. You may want a copied project to use the same TeX Live version as the original. Sometimes when you make a copy of an old project, new errors can show up because of changes in TeX Live. When this happens, you can either amend your project so that it is compatible with the latest version of TeX Live, or you can set the TeX Live version of your new copy to match the version of the original project it was copied from. You may need to have the version of TeX Live used in your Overleaf project match the version you use on your local machine. If you compile your projects locally as well as in Overleaf, to get consistent results you may wish to adjust the TeX Live version used by Overleaf to be compatible with the LaTeX version you use locally. You may be submitting to a journal or repository that compiles with a specific version of TeX Live. If you are submitting to a journal or repository that uses a specific version of LaTeX, compiling with the same or compatible version of TeX Live on Overleaf can help avoid errors at submission time. What is TeX Live? When Overleaf compiles your project, we use a standard set of programs, classes, and packages that come from the TeX Live LaTeX distribution. With each new release of TeX Live, enhancements are made, new features are provided, and sometimes old packages are retired. TeX Live is one of several available LaTeX distributions, and is widely seen as the standard distribution for Linux and other UNIX-like systems. What are some examples of changes between TeX Live versions? When a new version of TeX Live is released, there may be changes to the language (changes to LaTeX itself) or changes to the packages included in the distribution. As well as new features being added, some commands may become obsolete, and some packages may be removed. As a result, a project which compiles without errors with one version of TeX Live may not compile, or compile with errors, when a different TeX Live version is used. When Overleaf provides a new version of TeX Live for users, we like to provide a blog post that describes the changes that have gone into the latest version, and point out some of the issues that users may encounter. For examples, please see our TeX Live 2019 and TeX Live 2018 blog posts. What are the TeX Live versions? When a TeX Live version is released by TUG, Overleaf will test the new version and make it available - the length of time required for testing new TeX Live versions can vary. Currently, Overleaf provides TeX Live 2019, TeX Live 2018, TeX Live 2017, as well as two versions based on TeX Live 2016 (OV1 2016 and SL 2016), and versions based on TeX Live 2015 and TeX Live 2014 (SL 2015, SL2014). We do not recommend using versions older than TeX Live 2017 except in cases where older projects require these for compatibility reasons. How will this affect my Overleaf projects? Changing the TeX Live version of a project does not affect your project source - no changes will be made to your .tex files or other files that you provide. Changing the TeX Live version will change the version of LaTeX and the versions of the packages used to compile your project into a pdf. This may change what commands are available to you, and may change how some commands and packages work. Changing the TeX Live version may change the errors and warnings reported for your project, and may have an effect on the appearance of the generated PDF file. The TeX Live version that you choose for one project will not affect other projects - choosing the TeX Live version is a per-project option. Will this help with my arXiv submission? Currently arXiv compiles LaTeX projects using a modified version of TeX Live 2016. For projects that use a more recent version of TeX Live, this can result in incompatibilities when submitting to arXiv. Being able to select the version of TeX Live used to compile your project allows you to choose the most compatible version of TeX Live available for arXiv submissions. Please see our LaTeX checklist for arXiv submissions for more information. We do not recommend using versions older than TeX Live 2017 except in cases where older projects require these for compatibility reasons. Related articles LaTeX checklist for arXiv submissions Choosing a compiler
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