Quick instructions for installing Emacs 27 on CentOS 7 since it doesn't seem to be available in any popular yum repositories.

Install dependencies:

# Note: This installs dependencies for X11 as well.  Change this and the ./configure below if you don't want any X11 deps
sudo yum install \
    GConf2-devel \
    Xaw3d-devel \
    dbus-devel \
    dbus-glib-devel \
    dbus-python \
    gcc \
    giflib-devel \
    gnutls-devel \
    gpm-devel \
    gtk+-devel \
    gtk2-devel \
	ImageMagick \
	ImageMagick-devel \
    jansson-devel \
    libX11-devel \
    libXft-devel \
    libXpm-devel \
    libjpeg-devel \
    libpng-devel \
    libtiff-devel \
    libungif-devel \
    make \
    ncurses-devel \
    pkgconfig \
    texi2html \

Clone the emacs git repo and checkout the correct tag. Use git tag -l to see what tags are available.

git clone https://git.savannah.gnu.org/git/emacs.git
cd emacs
git tag -l
git checkout emacs-27.1.91

Run autogen and configure. When running ./configure, double check the output to ensure any features you need are enabled. E.g.: Look for Does Emacs use -ljansson? yes to make sure native json support will be compiled in. If something you need is not enabled, additional dependencies may need to be installed first.

./configure --without-selinux

Compile and install. Should go to /usr/local/bin by default, but can be changed with options to ./configure.

make -j4 && sudo make install