Please guide us about the copyright. Is it compulsory to observe it or not, e.g. software, publishing rights, according to Sharia with reference?

Praise be to Allah, the Lord of the Worlds; and blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

The meaning of the known sentence which is generally written on many books, i.e., "All rights are reserved" is that only the author, writer, composer, etc., are liable to benefit from all the efforts which they have spent in composing a book or translating it or verifying a scripture, etc.
Only the authors, writers…are liable for the right of profits, which are gained by printing and publishing their books. They do not only possess the material rights but they also have all other rights concerning the book or research work. We may classify these rights in two kinds:
1. Moral rights 2. Material rights.
The moral rights are based upon some important principles, some of which are as follows.
A. The authorship of the writer should be kept upon his book. The book should continuously be ascribed to its original writer. The writer does not have any right to give up these rights to any other person or organization. It is also not permissible for any one to adopt someone else's book by any means.
B. It is liable for a writer to reserve all the copyrights of his book such as the right of publication, supervision etc. So, he may stop the circulation of his book or printing it if he changes his views or adopts any other opinions.
2 The author has complete right over his work. He has the right to control it after publication, to stop it from being marketed, and even to stop its publication, due to a change in the author's opinions, for instance, regarding a given subject delt with in his book.
3. The author has the right to correct his work, add to it, modify it or take a part of it out before giving the publisher the permission to publish the work at another time.
Islam's opinion over the author's rights are clear. Dr. Bakr Bin Abdullah Abu Zaid summarized the Islamic opinion over this issue in his book Fiqh Al Nawazil [65/2] by saying: "The articles stipulating measures to protect the author's rights and to stop others from abusing his work conform with the Sharia because they give the author the right to preserve his value and his own performances from being abused by a second party.
As for the financial and material rights, they are similar to the financial privileges given to any author against any piece of work he does. These rights give the author a free hand in exploiting his own work in all legal ways. This right goes beyond the lifetime of the author to his legal inheritors.
But is it permissible for the author to sell a literary work he wrote? There is a disagreement among scholars over this issue. This disagreement is a follow up of the scholars' disagreement on teaching Qur'an:
Is it Halal (lawful) to be paid for teaching the Qur'an or not? Those who believe that it is forbidden to take compensation for teaching the Qur'an state the following evidences.
1. It is unlawful to take a compensation for worshipping one's Lord, Allah. Writing Sharia books is a form of worship. So, it is unlawful to take a compensation for writing Sharia books.
2. The fact that the author refuses to publish his book unless given a financial compensation is considered as hiding some knowledge of Sharia and this is forbidden. The Prophet said: "Whoever is aware of some knowledge and hides it, a bridle of Hell will be put around his neck on the Last Day". [Abu Dawood, Al-Tirmizi and Ibn Majah].
3. It is an objective in Sharia that the authentic knowledge be spread among Muslims so, the right of publication should be given to each and every Muslim willing to do it.
As for the scholars who think that it is lawful to take a compensation for teaching the Qur'an or for similar objectives they have the following evidences:
1. The Prophet said: "You are most entitled to take wages for doing a Ruqya with Allah's Book." [Reported by Imam Al-Bukhari]. So, if it is lawful to take a compensation for teaching the Qur'an, it is lawful to take it for the Sunnah and it is lawful to take a compensation for other related Sharia sciences.
2. The Hadith of Sahl Ibn Saad about using Qur'an as dowry for the bride. The Prophet said: "I have married her to you for the Qur'an you know". [Abu Dawood]. So, if it is lawful to use the Qur'an as a dowry that makes it lawful for the man to enjoy his wife, it is also lawful to take a compensation for teaching the Qur'an and spreading it. But it is more appropriate to give a compensation for the books written by an author who knows how to deduce rules from The Qur'an and the Sunnah.
3. Writing is a manual and intellectual work and the Prophet said: "Among the purest earnings is the one that the man gets by working with his hands and any valid and proper sale". [Ahmad]. The Prophet also said: "The purest thing you consume is from your earnings and your children are from your earnings". [Sunan].
4. Applying the known Fiqh rule: "Avoiding disadvantages (blight) is worthier and better than gaining benefits". If there are no rights reserved to the author, there will be a mess. The publisher might not take care of corrections. He might not take care of relating the verses and Hadith to their sources. Nowadays, the religious deterrent is weak among people. So, if the responsibilities are not clearly determined, books might be typed with many mistakes. This, in turn, could result in teaching people erroneous opinions and information. To conclude, the benefits that could be gained from making the publication public property are less important than the disadvantages that could result from this practice.
5. A permission of taking compensation for writing, teaching, etc., promote research work and encourage students and research workers to spend much effort to widen the field of research. No doubt, this is a major and basic endeavor to enhance the Muslim Ummah. If taking compensation for mental production is made forbidden, scientific work will be discouraged and the academic life of the Ummah will be deferred, especially nowadays when there is a lack of capable persons and the Ummah is in need of such persons and their work.
6. Some of the Muslim scholars have agreed upon the lawfulness of receiving compensation for writing (copying) the Qur'an as narrated from Ibn Abbas. He was asked about taking sums for writing (copying) the Qur'an. He replied: 'there is no harm in taking wages for it because they are copying only and eating with their handiwork'. And the Muslim scholars hold two various opinions about renting of the Qur'an. Some of the Hambali scholars even permitted taking payment for rental of the Qur'an. These two examples prove the legality of taking charges in the matters of Qur'an, which is the basis of other Islamic sciences. Then how could one say that taking compensation for composing books or any other research work is not permissible after the expenditure of much effort and money in that work?
7. Reserving the copy rights also protects books, or any research work from piracy. If reserving copyrights were not permitted for the writer then anyone, Muslim or non-Muslim, could make it a profitable source of income. There is no example in Shariah, which proves that taking benefits is not permissible for the original person while it is permissible for others. There are many other evidences mentioned by Dr. Abu zaid in his book Fiqh Al Nawazil.
The Fiqh Council passed a resolution in its fifth session which was held in Kuwait. The resolution is as follows:
1. Commercial name and address (trade mark, research work, and any invention) are the particular rights of their owners. These rights have monetary value, the Islamic Shariah respects such value, so violating them is forbidden.
2. The copyrights, inventions and research work are respected in Shariah. So, persons who are liable for these rights may act freely in their rights and violation of their rights is not allowed in any case.

Allah knows best.