i=installed
u=uninstalled
TM = Toolchain manager
VSC = Visual Studio Code

------------------
1.

1.9.1 (i TM)
...
2.8.0 (i TM)

------------------
2.

1.9.1 (i TM)
...
2.8.0 (i TM)
2.9.0 (i VSC)

------------------
3.

1.9.1 (i TM)
...
-2.8.0 (i TM, u VSC)
2.9.0 (i VSC)

------------------
4.

1.9.1 (i TM)
...
-2.8.0 (i TM, u VSC, deleted from file system)
2.9.0 (i VSC)

------------------
5.

1.9.1 (i TM)
...
-2.8.0 (i TM, u VSC, deleted from file system)
2.9.0 (i VSC, u VSC, i TM)