Projects are migrated to a newer version of FieldWorks when there is a model change. It is not possible to go back to using an older version of FieldWorks after migrating to a version with a model change unless you made a back-up of the project in the older version, and you are prepared to restore and use that back-up. Versions with model changes include 8.0.4, 8.3.1Beta1, and 8.3.2Beta2, and 9.0.4 Beta.

FieldWorks 9.1.22/24: Download options and Instructions.
FieldWorks 9.1.18/19/20/21: Download options and Instructions.
FieldWorks 9.1.15/16/17: Download options and Instructions.
FieldWorks 9.1.14: Download options and Instructions.
FieldWorks 9.1.12/13: Download options and Instructions.
FieldWorks 9.1.11: Download options and Instructions.
FieldWorks 9.1.8/10: Download options and Instructions.
FieldWorks 9.1.6/7: Download options and Instructions.
FieldWorks 9.1.5: Download options and Instructions.
FieldWorks 9.1.4: Download options and Instructions.
FieldWorks 9.1.2/3: Download options and Instructions.
FieldWorks 9.1.1: Download options and Instructions.
FieldWorks 9.0.17: Download options and Instructions.
FieldWorks 9.0.15/16: Download options and Instructions.
FieldWorks 9.0.11/12/14: Download options and Instructions.
FieldWorks 9.0.9/10 Release Candidate: Download options and Instructions.
FieldWorks 9.0.8 Release Candidate: Download options and Instructions.
FieldWorks 9.0.7 Release Candidate: Download options and Instructions.
FieldWorks 9.0.6 Beta: Download options and Instructions.
FieldWorks 9.0.5 Beta: Download options and Instructions.
FieldWorks 9.0.4 Beta: Download options and Instructions.
FieldWorks 8.3.12: Download options and Instructions.
FieldWorks 8.2.9: Download options and instructions.
FieldWorks 8.2.8: Download options and instructions.
FieldWorks 8.1.4: Download options and instructions.
FieldWorks 8.0.10: Download options and instructions.
FieldWorks 7.2.7: Downloads for 7.2.7.
FieldWorks 7.2.7: Downloads for 6.0.6, 7.0.6, and LL conversion to FLEx.