If you look here :
http://packages.ubuntu.com/search?keywords=librecad
you have information :
Pakiet librecad
precise (12.04LTS) (graphics): Computer-aided design (CAD) system [universe]
1.0.1+nolibs-2: amd64 i386
trusty (14.04LTS) (graphics): Computer-aided design (CAD) system [universe]
2.0
Public bug reported:
Why is there no LibreCad 2.0.8 package available for Ubuntu 15.10 ?
Librecad 2.0.8 has fixed a lot of bugs and has many new features as
compared to version 2.0.4.
** Affects: librecad (Ubuntu)
Importance: Undecided
Status: New
** Tags: needs-packaging
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Yo