hello @tima_t, thank you for reaching out, I will try to clarify as much as possible.
If you are running your node, hosting your compiler and your dApp is working with the current SDK and you are not using state channels then you don’t have to do anything. The release for the node is only relative to low level state channels communication, it doesn’t affect consensus and it doesn’t affects contracts.
If you are using the hosted compiler though (but more in general for contracts), you may want to check this one.
If you are using the API Gateway then you will have to update the SDK (because the node will receive the update).
If you are depending on state channels in your dApp you will have to eventually update both the node and the SDK if you want your node to be able to communicate with other nodes that may upgrade to the latest release.
About the problems you have experienced at the beginning of June, are they related to the changes announced in this post? I ask because we want to avoid as much as possible any disruption but sometime it is inevitable and the only way we have to mitigate it is to announce it beforehand and we are looking for the best way to do so.
And last but not least, the next big update that you can plan for is around mid September, where the HF will take place and will require an update of the node, SDK and probably for contracts too.