In Lotus Notes a field has Text type. The text contains multiple lines (witend-of-line between them). After migration we receive plain text on target.
1) Specify Target field type as Text and set Multi Line = True.
2) Create a formula column in your SDD with the following formula:
@ReplaceSubstring(docBody_L; @newline; "<br>")
Be sure to set the ReturnType to HtmlString.