This post covers overview of migrating/upgrading Oracle Application Server (9i/10g) to Fusion Middleware 11g (WebLogic) server.


1.Oracle WebLogic 11g R1 version is 10.3.1  where as WebLogic Server 10g R3 version is 10.3.0

2.Supported starting point for upgrade to Fusion Middleware 11g is
i) Oracle Application Server 10g R2 (10.1.2.X)
ii) Oracle Application Server 10g R3 (10.1.3.X)
iii) Oracle Application Server Portal 10g R2 (10.1.4.X)
iv) Oracle Identity Management (10.1.4X)

3. If you are on previous version of iAS (9.0.2, 9.0.3, 9.0.4) then first upgrade your application server to 10g R2/R3

4. If you are using OracleAS Single Sign-On or Oracle Delegated Administration Services (DAS), then you should be aware that there is no upgrade path to Oracle Fusion Middleware 11g for these components.
                Instead, if you are using Oracle Single Sign-On with Oracle Portal, Forms, Reports, and Discoverer, then you should maintain your existing 10g Release 2 (10.1.2) or 10g (10.1.4) Oracle Single Sign-On instance. 11g OID is supported with 10g Single Sign-On (SSO). More information here

upgrade to weblogic


5. Upgrade tools
i) Domain Upgrade
– use domain upgarde wizard if you are an existing WebLogic customer on WebLogic version 8, 9 or 10.X
       If you are on WebLogic 9.x or 10.x , you can also upgrade simply by pointing existing domain to 11gR1(10.3.1) binary.

ii) Smart Upgrade– If you have developed a custom J2EE application and running it on iAS (9i/10g) then use Smart Upgrade.

iii) Upgrade Assistant
– use upgrade assistant if you are using 9i or 10g AS (Application Server aka iAS) components like OHS, Forms, Reports, WebCache.

iv) Jdeveloper Migrator
– If you have developed ADF, SOA or WebCenter application and running it on Oracle Application Server 10g then use migration wizard in JDeveloper to migrate these applications to 11g.

To put it other way
a. Existing WebLogic customer use Domain Upgrade
b. Existing 10g iAS(forms/reports, portal, OHS, Webcache) use Upgrade Assistance
c. Existing 10g SOA/ADF/WebCenter Application then use Jdeveloper Migration Wizard in 11g
d. Exisitng J2EE application running on 10g iAS , use smart upgrade 

More information here

6)For upgrade assistance (to upgrade OHS, WebCache, Forms/Reports, Portal), upgarde assitance is re-runable and rolling upgrade is possible (upgrade middle tier first and upgrade metadata repository later)

7)If you use JDeveloper migrator to upgrade SOA Application (BPEL Project) from 10g to 11g then migration wizard automatically converts SOA Application to SCA (Service Component Architecture) model