Custom R binary for shiny-server

Hi,

I have systemwide R installation which is old. I want to shiny-server to run a custom location of R binary that I installed locally. To create an environment variable as described in the (documentation)[Shiny Server v1.5.16 Configuration Reference] I used the following configuration,

[Unit]
Description=ShinyServer

[Service]
Type=simple
ExecStart=/usr/bin/env bash -c 'exec /opt/shiny-server/bin/shiny-server >> /var/log/shiny-server.log 2>&1'
KillMode=process
ExecReload=/usr/bin/env kill -HUP $MAINPID
ExecStopPost=/usr/bin/env sleep 5
Restart=on-failure
RestartSec=1
Environment="LANG=en_US.UTF-8; R=/home/user/bin/R-4.1.1/bin/R"
StartLimitInterval=45
StartLimitBurst=3

[Install]
WantedBy=multi-user.target

Here /home/user/bin/R-4.1.1/bin/R is the custom location of R. While running a sample application I am getting the following error in the log file,

Listening on http://127.0.0.1:40367
Warning: Error in : .onLoad failed in loadNamespace() for 'Cairo', details:
  call: dyn.load(file, DLLpath = DLLpath, ...)
  error: unable to load shared object '/usr/local/lib/R/site-library/Cairo/libs/Cairo.so':
  libtiff.so.4: cannot open shared object file: No such file or directory
  136: <Anonymous>

library(Cairo) works perfectly in the local directory though.