5.1.20

siril

build from source
dependencies here (missing from the list: libheif-dev)

then in your home folder it's:

git clone https://gitlab.com/free-astro/siril.git

(if that fails try git:// instead of https://)
cd siril
./autogen.sh
CFLAGS=-g ./configure

make 

To run siril either:
make install
siril installs to /usr/local

Or -better-  run from the build folder without installing:
~/siril/src/siril

EDIT: this is also now necessary as of 29 March. In the ~/siril folder:
remove ~/siril/subprojects/librtprocess then...
git submodule update --init