In previous releases, FileStream class>>#write:, FileStream class>>#write:mode:, and FileStream class>>#write:mode:check:type: created instances which support read-write filestreams. However, according to the ANSI Smalltalk standard, they should create instances that support writeFileStream protocol only. Since these methods were introduced for ANSI compatibility, it is only reasonable that they should perform according to the standard. The effect of this change is that it is no longer valid to use any of the readFileStream protocol with a filestream object created using these methods.