Collaboration can happen outside the Scrum Team from other stakeholders when there is a special work request to be relayed down to the Scrum Team. In other words, a Scrum Team does not live in a black box without interaction with other teams, sometimes these teams could be non-Scrum Teams. So if DevOps requests SW upgrades to a Scrum Team, is this the Scrum Master's or Product Owner's role in communicating this to your team? I think it is the Scrum Master who should relay this software upgrade, the team's voice, and the team helper by sharing new information, not the PO. When you give the PO these roles, it interferes with the coaching of the team because SM is supposed to protect the team from the PO. Experts have noted this agreement, such as from Mountain Goat Software, stating "The usual example is that the ScrumMaster must protect the team from an overly aggressive product owner," 1.
I have read this question several times and if I understand your question correctly, I don't think you fully understand the concept of Scrum, and how it's embedded in the organization.
Let's start with what "IT requests SW update" means - do you mean workstations? (operating system, software) or software for servers, virtual machines?
If so, managing the company's software versioning should be a completely different process, separated from product development. Since IT requires software upgrade, it should itself inform the teams or their superiors in the company structure (not the product structure).
Scrum as a framework is embedded in the domain of product development. If the IT regulations don't result directly from the ongoing or planned work within the product, these processes should be completely separate. Of course, they can have an impact on the work of the development team, so appropriate roles in Scrum can participate in this process:
Product Owner - as a person responsible for product development, priorities, etc. should be informed about the need to perform such work, as in a given iteration it may affect the capacity. If such work is planned in advance, this information can help the PO to plan the upcoming work appropriately and possibly modify needs and goals.
Scrum Master - as a servant leader - if there are any problems regarding such work (sprint goal is threatened, lack of PO consent to include the work in the team's work plan, etc.), may help the team to carry out this (using the tools available for him), but he should be informed about such problems.
Both of these roles may have an impact on it, but they shouldn'tt be the addressee or the transmitters of this type of information resulting from internal procedures - not product development.
Finally, I would like to add that SM should not protect the team from PO. If he has to do this, there is something wrong with this relationship. The PO should work together with the team to develop the product as valuable as possible. SM should support them in understanding the framework's processes, support continues improvment, and solve problems that may reduce or block effective work. The development team, PO and SM should be one team with a common goal. In healthy relationships, no one has to protect anyone from anyone.
The Product Owner would be accountable, but not necessarily responsible for this work.
The person playing the role of the Product Owner is accountable for managing the Product Backlog. This includes clearly expressing Product Backlog Items, ordering the Product Backlog Items, ensuring that the current state of the Product Backlog is visible and transparent to all stakeholders, and ensuring that the Scrum Team(s) working from the Product Backlog understand the work to the necessary level of detail to execute on it.
Since the Product Backlog is "an ordered list of everything that is known to be needed in the product", the need to perform software upgrades would be captured in the Product Backlog. Since it is something to be captured in the Product Backlog, the Product Owner would be accountable.
However, the Product Owner may involve the Development Team in various activities related to Product Backlog management. For example, the Development Team may be responsible for expressing Product Backlog Items of a highly technical nature and working with the Product Owner on ordering those with the other items. Regardless of who is involved in Product Backlog management, the Product Owner is always accountable.
I would also recommend trying to understand the role of the Scrum Master better. The description given contains some misconceptions.