diff --git a/apt-install_R_dependencies.sh b/apt-install_R_dependencies.sh
index 1f4faf0..ff929bd 100755
--- a/apt-install_R_dependencies.sh
+++ b/apt-install_R_dependencies.sh
@@ -7,7 +7,7 @@
 
 wget -qO- https://cloud.r-project.org/bin/linux/ubuntu/marutter_pubkey.asc | sudo tee -a /etc/apt/trusted.gpg.d/cran_ubuntu_key.asc
 sudo add-apt-repository --yes "deb https://cloud.r-project.org/bin/linux/ubuntu $(lsb_release -cs)-cran40/"
-#sudo add-apt-repository --yes ppa:c2d4u.team/c2d4u4.0+
+sudo add-apt-repository --yes ppa:c2d4u.team/c2d4u4.0+
 
 sudo apt install --no-install-recommends -y \
 r-cran-ape \
@@ -17,6 +17,7 @@ r-cran-vioplot \
 r-cran-plyr \
 r-cran-dplyr \
 r-cran-ggplot2 \
+r-cran-stringi \
 r-cran-stringr \
 r-cran-seqinr \
 && sudo apt clean && apt purge && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
diff --git a/install_R_deps.R b/install_R_deps.R
index 179a6de..4f098d1 100755
--- a/install_R_deps.R
+++ b/install_R_deps.R
@@ -40,7 +40,7 @@ repository = 'https://CRAN.R-project.org' # ; 'http://cran.rstudio.com' # 'https
 # 2024-04-13: removed "cluster", "dendextend", "factoextra", which are only required by hcluster_pangenome_matrix.sh, 
 #    which is distributed through the GET_HOMOLOGUES GitHub repo.
 # 2024-04-15: replaced devtools for the much lighter remotes.
-required_packages = c("remotes", "ape", "gplots", "vioplot", "plyr", "dplyr", "ggplot2", "stringr", "seqinr")
+required_packages = c("remotes", "ape", "gplots", "vioplot", "plyr", "dplyr", "ggplot2", "stringi" "stringr", "seqinr")
 
 
 local_lib = "./lib/R"