% opam upgrade
The following actions will be performed:
  ↻  recompile ocamlfind       1.6.2                          [upstream changes]
  ∗  install   conf-emacs      1
  ↻  recompile flexdll-windows 0.34                           [upstream changes]
  ↗  upgrade   ocp-build       1.99.13-beta to 1.99.16-beta
  ↗  upgrade   menhir          20160303 to 20160526
  ↗  upgrade   cppo            1.3.1 to 1.3.2
  ↗  upgrade   batteries       2.4.0 to 2.5.2
  ↻  recompile omake           0.9.8.6-0.rc1                  [uses ocamlfind]
  ↻  recompile easy-format     1.2.0                          [uses ocamlfind]
  ↻  recompile caml-mode       4.02
  ↻  recompile ocaml-windows64 4.02.3                         [upstream changes]
  ↻  recompile biniou          1.0.9                          [uses ocamlfind]
  ↻  recompile ocaml-windows   4.02.3                         [uses ocaml-windows64]
  ↻  recompile yojson          1.3.2                          [uses cppo, ocamlfind]
  ↻  recompile merlin          2.3.1                          [uses ocamlfind]
  ↗  upgrade   tuareg          2.0.9 to 2.0.10
===== ∗  1   ↻  10   ↗  5 =====
Do you want to continue ? [Y/n] y

=-=- Gathering sources =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
[menhir.20160526] http://gallium.inria.fr/~fpottier/menhir/menhir-20160526.tar.gz downloaded
[cppo.1.3.2] https://github.com/mjambon/cppo/archive/v1.3.2.tar.gz downloaded
[ERROR] Bad checksum for /home/kaustuv/.opam/packages.dev/ocp-build.1.99.13-beta/1.99.13-beta.tar.gz:
          - 52ca4a83d6722f3d75e74019f10aad90 [expected result]
          - 46e876a35fd905df5be9b062e773b7f6 [actual result]
        This may be fixed by running `opam update`.

[ERROR] Bad checksum for /home/kaustuv/.opam/packages.dev/ocp-build.1.99.16-beta/1.99.16-beta.tar.gz:
          - 5935b00680c0d938c5052b8fef45cbac [expected result]
          - bfd12f6e67e1db9b9fcf73f96cad71c8 [actual result]
        This may be fixed by running `opam update`.

[tuareg.2.0.10] https://github.com/ocaml/tuareg/releases/download/2.0.10/tuareg-2.0.10.tar.gz downloaded
[batteries.2.5.2] https://github.com/ocaml-batteries-team/batteries-included/archive/v2.5.2.tar.gz downloaded
[ERROR] The sources of the following couldn't be obtained, aborting:
          - ocp-build.1.99.13-beta
          - ocp-build.1.99.16-beta
        (This may be fixed by running 'opam update')