Because of vendor update situations and other causes I (and my grad 
students) have done what you require more than once.

The easiest approach -- if you have adequate disk space, etc., it to use 
Virtual Box (licensed for free) or VMWare (variant depending upon what 
you need -- the only one that is licensed for free is VMWare Player) and 
create under a type 2 hypervisor a virtual machine an instance of the 
exact OS and related environment that you need.

The other method is a merry chase, depending upon the situation.

First, find all of the unresolved library and header files that the 
installable RPM needs.  See if these are available from any reliable 
distro or source for the OS release you are using.  This may take 
repeated iterations.  Say, X is needed, and you find X (that supports 
exactly what you need, say blah.3.1-4 not blah.3.1-3 nor blah.3.1-5, 
unless you are very lucky and any blah.3 will suffice.  After you have 
fixed the need for X, you may find a need for Y, etc., and then you 
continue.

If you must build from source (say, a .SRPM), then the build environment 
must be the same, including the C/C++ compiler and the C/C++ 
library(ies), along with whatever other utilities are needed.  If you 
are lucky, and the .SRPM wanted say libblah.4.2-1 but the current 
libblah.6.x back supports the older functionality, you may be able to 
build simply by doing a soft (false name) link between the current 
libblah and the libblah version you need.  This sometimes works.

If this does not work, and the libblah and other utilities are not 
available in the correct version for the environment (OS plus whatever) 
upon which the application is to be run, then you must modify the source 
code (after expanding the .SRPM to a full source) to use the current 
syntax and capabilities that are in use.  This may require minor 
rewriting, or it may require significant re-design and re-implementation.

Finally, once the desired application is built and runs (runs is 
critical -- it may build and install, but fail to run because of other 
dependencies), you must test that it still works to your needs, 
particularly on "edge" cases. Regrettably, this is not always a simple 
process and in some cases requires a major re-design.

If you are not both knowledgeable and "skilled", this can be a learning 
experience and a large investment of time.  Even if both conditions are 
met, it still can be a large investment of time.


On 6/29/21 8:56 AM, Dave Dykstra wrote:
> Often an rpm from an older Linux OS will still work on a newer one, but
> it depends on how complicated it is.  It would be best to recompile it
> from the source rpm and make a new binary rpm out of it based on RHEL7,
> although it is likely that some porting will also need to be done for
> that.
> 
> An alternative is to install your SL6 rpm into a CentOS6 docker or
> singularity container, and run the docker or singularity application on
> the newer operating system.
> 
> In any case, you probably are going to need some help, and I don't know
> if there is anybody on this mailing list that provides such professional
> services.  I suggest googling for that.
> 
> Dave
> 
> On Tue, Jun 29, 2021 at 06:43:12AM +0000, Nick Matchett wrote:
>> I hope that someone could help me identify an individual or business that would be able to help me with the following problem.
>>
>> My business has some software that we acquired the responsibility to maintain and support, and currently sits on Scientific Linux version 6.3.  Unfortunately, we are at a stage where our customers are asking to bring the software onto a more current version of a Linux platform.
>>
>> We would like to migrate to Red Hat or CentOS version 7.9  (or perhaps version 8)
>>
>> We have been working on a migration from Scientific Linux 6.3 to Redhat 7.9.
>>
>> Unfortunately, we have limited Linux OS skills in our business, and we have approached this with a fresh RH 7.9 install and then applying the RPM of our software.  There is a big mismatch between Scientific Linux 6.3 to Redhat 7.9 in terms of libraries, file structure and type of libraries between the software and we have not been able to reconcile those.
>>
>> I would appreciate any suggestion or advice on the best upgrade path to achieve this update  and would be happy to take recommendations on individuals or companies who might be interested in a professional service engagement to help solve the problem.
>>
>> Thanks in advance