Downgrade is one of the commands of the pub tool.
$ pub downgrade [args] [dependencies]
Without any additional arguments,
pub downgrade gets the lowest versions of
all the dependencies listed in the
in the current working directory, as well as their transitive
$ pub downgrade Resolving dependencies... (1.2s) + barback 0.13.0 + collection 0.9.1 + path 1.2.0 + source_maps 0.9.0 + source_span 1.0.0 + stack_trace 0.9.1 Changed 6 dependencies!
pub downgrade command creates a lockfile. If one already exists,
pub ignores that file and generates a new one from scratch, using the lowest
versions of all dependencies.
pub get documentation for more information
on package resolution and the system package cache.
Downgrading specific dependencies
It’s possible to tell
pub downgrade to downgrade specific dependencies to the
lowest version while leaving the rest of the dependencies alone as much as
possible. For example:
$ pub downgrade test Resolving dependencies... barback 0.15.2+2 bot 0.27.0+2 browser 0.10.0+2 chrome 0.6.5 collection 1.1.0 path 1.3.0 pool 1.0.1 source_span 1.0.2 < stack_trace 0.9.2 (was 1.1.1) stagexl 0.10.2 < test 0.10.0 (was 0.11.4) These packages are no longer being depended on: - matcher 0.11.3 Changed 3 dependencies!
If you are downgrading a specific dependency, pub tries to find the highest versions of any transitive dependencies that fit the new dependency constraints. Any transitive dependencies are usually also downgraded as a result.
Getting a new dependency
If a dependency is added to the pubspec before
pub downgrade is run,
it gets the new dependency and any of its transitive dependencies,
placing them in the
.packages file. This
is the same behavior as
Removing a dependency
If a dependency is removed from the pubspec before
pub downgrade is
run, it removes the dependency from the
thus making the dependency unavailable for
importing. Any transitive dependencies of the removed dependency are
also removed, as long as no remaining immediate dependencies also
depend on them. This is the same behavior as
Downgrading while offline
If you don’t have network access, you can still run
Because pub downloads packages to a central cache shared by all packages
on your system, it can often find previously downloaded packages
without needing to use the network.
However, by default,
pub downgrade tries to go online if you
have any hosted dependencies.
If you don’t want pub to do that, pass it the
In offline mode, pub looks only in your local package cache,
trying to find a set of versions that work with your package from what’s already
pub downgrade command supports the
pub get options.
For options that apply to all pub commands, see Global options.