On Tue, Jun 01 2021, pukkamustard wrote:

> Hi,
>
> Xinglu Chen <public@yoctocell.xyz> writes:
>
>> On Mon, May 10 2021, pukkamustard wrote:
>>
>>> * gnu/packages/ocaml.scm (ocaml-migrate-parsetree): Update to 
>>> 2.1.0.
>>>   (ocaml-migrate-parsetree-1): New variable.
>>
>> What’s the reason for keeping the old version of
>> ‘ocaml-migrate-parsetree’?
>
> There are two reasons:
>
> 1. ocaml4.07-* packages seem to require ocaml-migrate-parsetree 
> version 1.*.
> 2. There are some ocaml-* packages that require the old version of 
> ocaml-migrate-parsetree (e.g. ocaml-bisect-ppx or ocaml-mdx).
>
> There are a couple of other ocaml packages with two versions. The 
> older version is just named ocaml4.07-NAME (e.g. ocaml-sexplib is 
> version 0.14.0 and ocaml4.07-sexplib is version 0.11.0). For 
> ocaml-migrate-parsetree this does not work as some ocaml-* 
> packages require the old version - thus ocaml-migrate-parsetree-1.

OK, thanks for the explanation.