After migrate from :

script-security : 1183.v774b_0b_0a_a_451
workflow-cps : 2801.vf82a_b_b_e3e8a_5

to :

script-security : 1218.v39ca_7f7ed0a_c
workflow-cps : 3536.vb_8a_6628079d5

Our shared library throw the exception : Scripts not permitted to use new java.util.Properties. Administrators can decide whether to approve or reject this signature.

The library use the readProperties Pipeline Utility Steps and is globally configured in Jenkins in the "Global Pipeline Libraries" section so it might be trusted, meaning they run without “sandbox” restrictions