Source Programs: Migration from High Level Assembler Release 1, High Level Assembler Release 2, High Level Assembler Release 3, High Level Assembler Release 4, High Level Assembler Release 5, Assembler H Version 2 or DOS/VSE Assembler to High Level Assembler Release 6, requires an analysis of existing assembler language programs to ensure that they do not contain macro instructions with names that conflict with the High Level Assembler Release 6 symbolic operation codes, or SET symbols with names that conflict with the names of High Level Assembler Release 6 system variable symbols.

Except for these possible conflicts, and with appropriate High Level Assembler option values, assembler language source programs written for High Level Assembler Release 1, High Level Assembler Release 2, High Level Assembler Release 3, High Level Assembler Release 4, High Level Assembler Release 5, Assembler H Version 2 or the DOS/VSE Assembler, that assemble without warning or error diagnostic messages, should assemble correctly using High Level Assembler Release 6.

Object Programs: Object programs generated by High Level Assembler Release 6 in any one of the supported operating systems can be migrated to any other of the supported operating systems for execution.

The object programs being migrated must be link-edited in the target operating system environment before execution.

Be aware of the differences in the code generated by system macros in the supported operating systems. Operational facilities available on the source operating system but not available on the target operating system should not be specified for any program which is required to be compatible, either during assembly or link edit.