how to include latest libreoffice in a custom docker image?

Following is the Dockerfile. With this it install libreoffice version 6.x. Is there a way to make it version 7? Thanks.

> FROM node:12.16.3-buster-slim
> 
> # Installs git, unoconv and chinese fonts RUN apt-get update && apt-get -y
> install \
>     git \
>     unoconv=0.7-1.1 \
>     ttf-wqy-zenhei \
>     fonts-arphic-ukai \
>     fonts-arphic-uming \
>     fonts-indic \ && rm -rf /var/lib/apt/lists/*
> 
> ENTRYPOINT /usr/bin/unoconv --listener
> --server=0.0.0.0 --port=2002

You can take a look at this image - Docker Hub. You will need to download the version and do a dpkg install. you can download the tar.gz from the website and keep it while building.

RUN apt-get install -y default-jre libxinerama1 libdbus-1-dev libcups2-dev libx11-xcb-dev

#Installing LibreOffice_7.1.3
WORKDIR /soffice
COPY LibreOffice_7.1.3_Linux_x86-64_deb.tar.gz /soffice
RUN tar -xvf LibreOffice_7.1.3_Linux_x86-64_deb.tar.gz
RUN dpkg -i LibreOffice_7.1.3.2_Linux_x86-64_deb/DEBS/*.deb

#Configuring SOFFICE client for terminal operations
RUN ln -s /opt/libreoffice7.1/program/soffice /usr/local/bin/soffice
RUN ln -s /opt/libreoffice7.1/program/soffice /usr/local/bin/lowriter

According to packages.debian.org, buster-backports currently has 1:7.0.4~rc2-1~bpo10+2 (guessing from node:12.16.3-buster-slim).