How can I test the impact of a single Meteor package upgrade?

I am facing a weird server crash problem and was able to track this down to a difference between Meteor 1.5 (running) and 1.5.1 (crashing). The updater tells me that these packages have been touched:

accounts-base              upgraded from 1.3.0 to 1.3.1
accounts-password          upgraded from 1.3.6 to 1.4.0
allow-deny                 upgraded from 1.0.5 to 1.0.6
babel-compiler             upgraded from 6.19.1 to 6.19.4
boilerplate-generator      upgraded from 1.1.0 to 1.1.1
ddp                        upgraded from 1.2.5 to 1.3.0
ddp-client*                upgraded from 1.3.4 to 2.0.0
ddp-common                 upgraded from 1.2.8 to 1.2.9
ddp-server*                upgraded from 1.3.14 to 2.0.0
dynamic-import             upgraded from 0.1.0 to 0.1.1
ecmascript                 upgraded from 0.8.0 to 0.8.1
ecmascript-runtime-client  upgraded from 0.4.1 to 0.4.2
email                      upgraded from 1.2.1 to 1.2.3
meteor                     upgraded from 1.6.1 to 1.7.0
minimongo                  upgraded from 1.2.0 to 1.2.1
modules                    upgraded from 0.9.0 to 0.9.2
mongo                      upgraded from 1.1.18 to 1.1.19
npm-bcrypt                 upgraded from 0.9.2 to 0.9.3
shell-server               upgraded from 0.2.3 to 0.2.4
webapp                     upgraded from 1.3.16 to 1.3.17

So I tried to update them one by one, to find the ‘culprit’. But Meteor won’t allow me to do so. It automatically re-adjusts the versions file to the versions valid to the respective Meteor version. Seems as if the versions are pinned. Is there a way to force Meteor to accept incompatible versions?

@waldgeist What error/debug message(s) are you getting/seeing after/during the crash in the console?

@martineboh: The actual problem is described here:

I also filed an issue in the Meteor repo:

A few packages you can remove and replace by there children. For example meteor-base you can remove, and add the components you need individually. I guess you can than also upgrade them individually.

This is for the packages I know of.

meteor-base
  meteor                     upgraded from 1.6.1 to 1.7.0
  webapp                     upgraded from 1.3.16 to 1.3.17
  underscore
  hot-code-push
  ddp                        upgraded from 1.2.5 to 1.3.0
    ddp-client*                upgraded from 1.3.4 to 2.0.0
    ddp-common                 upgraded from 1.2.8 to 1.2.9
    ddp-server*                upgraded from 1.3.14 to 2.0.0