The Italians used airplanes in the Turkish war the year before the Balkan war.
If you fought WWI in 1907 and it was over very quickly after the Germans ran out of nitrates for ammunition, then armor might not have been developed until the next big war.
OK, Russia and Japan get into it. Russia has competent leadership (the Tsar gets blown up and someone is regent) and no revolutionary movement (the Tsar gets blown up with his family and pisses off the peasantry) and so keeps it's navy at home and just sends more troops and supplies, buying locomotives for the transiberian and steamships for Baikal to get them there.
Then the US president doesn't get involved, the war lasts longer, more Russian troops get battle experience, and the war ends in a Russian "victory" after Japan goes bankrupt. Russia is too broke to take over Korea as a colony and gets brownie points from the Russophobe liberals of Europe by allowing Korean independence.
When Austria-Hungary takes over Bosnia in 1907 the Russians threaten war. Austria-Hungary doesn't back down. Russia doesn't either. Germany doesn't dare do nothing or it will lose it's only major and dependable ally, and it can't attack Russia without attacking France first. The German army attacks France through Belgium. The French army moves into Belgium as per plan Michael to defend Belgian neutrality and the armies bog down along the central Belgium high ground, with the canal ports still in French hands.
Russia's experienced troops, back less than a year from Siberia, stomp the Austro-Hungarian army even worse than in OTL. The Serbs don't do as well since they have not had the Balkan wars to test their officers and doctrines, but they do hold the Danube when the Austro-Hungarians have to yank away their troops to hold the Carpathians against the Russians.
The Germans launch multiple attacks against the dug in French and keep pushing them back all the way across Belgium, but the pace is slow enough for evacuations to preserve the French and Belgian industrial capacity until the war is over , which is when the Germans run out of ammo.
The British send a token expeditionary force of one division. It keeps getting more reinforcements as they keep getting killed or wounded. Mostly Britain just blockades Germany until it evacuates Belgium.
Without Turkey in the war the Russians keep getting ammo and other supplies. The Germans can pull troops out of the Western Front and attack them, but they can't force a decision in only one year. So they sign an armistice and then a treaty. This treaty is considerably milder in form and harsher in enforcement. The Germans pay reparations to the Belgians, French, and Russians for the damage they did to their civilian property, and the Austrians pay reparations to the Russians and Serbians. The reparations are much less because the damage of the war is much less. Belgium got hosed and got the most reparations because they were the battlefield. Germany levys a property tax to compensate people who leave the annexed lands.
Without Italy in the war the Slovenians get Trieste as a seaport. Rumania stayed out because their King was German, so they don't get Transylvania or the Russian occupied lands. Hungary pulls out of Austria-Hungary and is much larger and with significant minorities, keeping Ruthenia, Vojvodina, Transylvania, and the Hungarian parts of Slovakia as a reward. Czechs and Slovaks get nations. The Czechs don't get the Sudetenlands, which stay part of Austria, which does merge with Germany. Silesia winds up part of Russian Poland. Serbia gets Bosnia and Croatia.
After the war the Germans are forbidden to build tanks, planes, any naval forces, or artillary over three inches, in effect preventing them from attacking any kind of fortified position. Nobody else build tanks because nobody else wants to fight as big and bloody a war as the one year of slaughter called the Last War.