You can migrate modeling resources from version 6 of the Rational
UML modeling products to version 7, but you cannot save the new modeling
resource in a format that is compatible with version 6. To continue simultaneous
model development in both versions of the products, the corresponding team
repository must be split into two branches, one for version 6 and another
one for version 7 model development.
Merging models
In a team environment where some members
will be using the version 7 of the modeling products and others will be using
the version 6, simultaneous model development in both versions can be performed
if the corresponding team repository is split into two branches, a branch
for version 6 and a branch for version 7. The auto-migration feature in version
7 enables development to continue on both branches, with model changes on
the version 6 branch merged into the version 7 branch. Because profiles cannot
be merged, they should only be changed in a single branch, the version 6 branch.

For
more information about merging models in the Rational modeling products, consult
the articles on the IBM's developer Works Web site: www-128.ibm.com/developerworks/rational/products/rsa/.
Migrating UML profiles
The migration of profile
(.epx) resources from version 6 to version 7 is performed automatically in
memory when the profile is opened. If the profile is modified and saved, the
saved profile will be in version 7 format. If the profile is not saved, it
will remain in the version 6 format on disk. This has advantages when working
in a dual branch team environment.
A version 6 profile can be deployed
in a version 7 profile. When a model is opened that has a version 6 profile
applied, the profile itself will automatically be opened and migrated (in
memory) to version 7.
- If the profile was deployed in a plug-in in the product installation and
it is never saved, the profile on disk remains in a version 6 format.
- If the profile resides in a version 7 workspace project, the profile reference
in a model will cause the version 6 profile to be opened and you may be prompted
to update the ProfileBase version. Do not update the version 6 profile and
do not save the profile. This will ensure the version 6 format is maintained.
Note: Changes to the profile must be made in the version 6 branch, and
the version 6 profile should be used in the version 7 products.
When
a branch realignment is to be performed, all version 6 profiles should be
re-registered (deployed) in version 7 before attempting to migrate and merge
the models. Otherwise, the migrated version 6 model will be referring to a
newer version of the profile that does not exist. The result will be either
the loss of applied stereotypes or model corruption.
Migrating UML models
The migration of model (.emx)
resources from version 6 to version 7 is transparent to the user. You can
open the model in version 7 of a Rational UML modeling product and the resource
is automatically converted to version 7. When opening a version 6 model, you
are prompted to update various applied profiles to newer versions, and this
will allow the model to be used in the version 7 of the product.
Note: There
is no support for saving a model back in a version 6 format. Once the model
is saved, it can only be used in a version 7 of the modeling products.
When
working in team environment with multiple repository branches, before attempting
to migrate a model from version 6 to 7, all version 6 profiles that are applied
to that model must first be re-registered in the version 7 product. When the
version 6 model is migrated, these profiles will automatically be opened,
migrated (in memory), and resolved.
Migrating diagrams
The migration of diagram (.dnx)
resources from version 6 to version 7 is performed automatically when the
diagram resource is opened for the first time in version 7; however, there
is no support for saving a diagram resource back in the version 6 format.
Once the diagram is saved, it can only be used in version 7 of the Rational
UML modeling product.