Thank you.
Actually, it did work.
I simply did not understand the output of st.
I thought I was still on v0.17.1+ as it shows as such (see below).
Turns out the #a0d44f6 refers to v0.14.1 which I wanted.
Why does is say “v0.17.1+” is installed when actually it is an earlier version?
(v1.0) pkg> activate .
(DecisionTrees) pkg> st
Project DecisionTrees v0.0.1
Status `C:\Users\bernhard.konig\Documents\ASync\home\Code\Julia\DecisionTrees.jl\Project.toml`
[336ed68f] CSV v0.4.2
[a93c6f00] DataFrames v0.17.1+ #a0d44f6 (https://github.com/JuliaData/DataFrames.jl.git) ⚲
[033835bb] JLD2 v0.1.2
[a15396b6] OnlineStats v0.21.0
[92933f4c] ProgressMeter v0.9.0
[438e738f] PyCall v1.18.5
[295af30f] Revise v1.1.0
[2913bbd2] StatsBase v0.28.1
[ade2ca70] Dates
[8bb1440f] DelimitedFiles
[8ba89e20] Distributed
[9a3f8284] Random
[10745b16] Statistics