Prophet Muhammad (SallAllah-u-Alaihi-wa-Sallam) said: Whoever introduces a new thing in our affair (Deen) will be rejected.
(Sahih Bukhari: Kitabus Sulah and Sahih Muslim: Kitab ul Aqdiyya)

Prophet Muhammad (SallAllah-u-Alaihi-wa-Sallam) said: The worst deeds of all are innovations and every innovation is bidah and every bidah is deviation and every deviation will be in hellfire.
(Nasai Vol.1 pg 179, Minhaaj ul Muslimeen pg 514, Sanad: Sahih)

Innovations in Deen are very dangerous; a Muslim should always beware of them, the worship of innovators isn’t accepted.

Prophet Muhammad (SallAllah-u-Alaihi-wa-Sallam) said: whoever innovates in it (Medina) or shelters an innovator has the curse of Allah, the angels and all people on him, his obligatory or optional (acts of worship) aren’t accepted.
(Sahih Bukhari: Kitab ul Manasik and Sahih Muslim: Kitab ul Hajj)

Unfortunately the above hadith has been ignored by the people of Medina who shelter all sorts of innovators in Medina.

Prophet Muhammad (SallAllah-u-Alaihi-wa-Sallam) said: Before me whichever prophet Allah sent to his ummah had companions and supporters who followed the prophet’s sunnah and his orders, then after them ignorant people will be born who will not do what they claim, and do things which weren’t ordered to them. Whoever does jihad with his hand against these people is a believer, who does jihad with his tongue is a believer, whoever does jihad with his heart is (also) a believer (considering it wrong at least in his heart) and after that faith even the size of a seed ceases to exist.
(Sahih Muslim: Kitab ul Iman)

Points:

1) The people who are ignorant don’t practice what they preach.         

2) And do things which weren’t ordered (meaning create innovations).

We have to strive against such people, with our hands if possible, with our tongues if not possible by hands, with our hearts if not possible with hand and tongue. If we do not strive against such people with even our hearts then we don’t have faith left even the size of seed, so how can a person practicing such things have faith?

We should also consider the fact that we have been ordered to strive against such people so how would it be allowed for us to pray salaah behind such people or join hands with them in any religious activity, such acts would be contrary to striving against them.

Prophet Muhammad (SallAllah-u-Alaihi-wa-Sallam) said: I am your predecessor at the Lake-Fount (Kauthar) and some men amongst you will be brought to me, and when I will try to hand them some water, they will be pulled away from me by force whereupon I will say: ‘O Lord, my companions!’ (In some narrations the words are my followers or from my ummah) Then the Almighty will say: ‘You do not know what they did after you left, they introduced new things into the religion after you’.
(Sahih Bukhari: Kitab ul Fitan)

People practicing bidaat won’t be allowed to go near the Prophet Muhammad (SallAllah-u-Alaihi-wa-Sallam) on the Day of Judgment as bidaat are a form of shirk and kufr, making of shariah is for Allah alone.

Or have they associates who have prescribed for them any religion that Allah does not sanction? And were it not for the word of judgment, decision would have certainly been given between them; and surely the unjust shall have a painful punishment.
(Surah Ash-Shura: ayah 21)

Allah has made the Deen and no person has the right to add or subtract anything in it, adding something in Deen means that Allah’s Deen wasn’t complete and such a thought is obviously kufr, only Allah has the right to make shariah and certainly our Deen is complete.

This day have I perfected for you your religion and completed my favor on you and chosen for you Islam as a religion.
(Surah Maida: ayah 3)

Please note that Islam is not against innovations in technology and skills but rather against innovations in Deen, meaning the Deen should be practiced in its original form.